Patent Publication Number: US-2023143802-A1

Title: Systems and methods for improved web-based document retrieval and object manipulation

Description:
BACKGROUND 
     Technical Field 
     The present disclosure generally relates to web-based document retrieval techniques, and to systems and methods for retrieving, viewing, and manipulating objects in web documents. In particular, and without limitation, the present disclosure relates to systems and methods for providing improved web-based document retrieval techniques, including systems and methods for performing manipulations on objects within retrieved web documents once these objects are visible to a user. 
     Background Information 
     The Internet provides a wide array of resources and services. Among other things, the Internet enables users to access inter-linked documents of the World Wide Web (the “web”). Modern web documents, such as web pages, are able to seamlessly integrate textual information with images, streaming video, and other interactive media. Search engines enable web users to locate relevant web documents or pages. For example, upon receipt of a search query from a user, a search engine may provide the user not only hyperlinks associated with the query, but also images, videos, and additional online content, such as advertisements, that are related to the search query. 
     Hyperlinks enable users to navigate the World Wide Web. For example, by clicking on an article on a web site of a news provider, the user may be presented with the textual content of the article. Such information may be supplemented by images and/or one or more streaming videos related to the article. 
     While modern web documents can greatly expand the richness of online content available to a user, related images, streaming videos, and other additional content may increase the volume of data to be downloaded. Depending on a user&#39;s connection speed and computer resources, the user often must wait or deal with extended delays to download an entire web page. 
     There also other drawbacks with modern web documents. For instance, images and other additional content is rarely clustered around a single portion of a web document or page. More commonly, such content is positioned throughout the web page in order to capture the user&#39;s attention as the user scrolls through the page. However, in many instances, a user may only view a selected portion of a web page in order to obtain desired information. Moreover, while a search engine may return a large number of results and content associated with a search query, the user may only view several of these results. In such an instance, the, user has downloaded all of the additional media content provided by the search engine, but has only viewed a small subset of that content. 
     In view of the foregoing, there is a need for improved systems and methods for selectively loading and manipulating multimedia content in a web document based on, for example, a portion of that web document visible to a user. Such systems and methods may be implemented in computer-based environments, such as the Internet and network environments that provide online content to users. 
     SUMMARY 
     Consistent with embodiments of the present invention, a computer-implemented method for manipulating objects in a web document is provided. The method identifies a portion of a retrieved web document that is displayed to a user. The identified portion includes a first boundary and a second boundary in a scrolling direction. The method then selects at least one object from the retrieved web document, and the at least one selected object is associated with a corresponding manipulation. The method detects whether a portion of the at least one selected object falls between the first and second boundaries, and then performs the corresponding manipulation of the at least one selected object when the portion of the selected object falls between the first and second boundaries. 
     Consistent with additional embodiments of the present invention, a apparatus having a storage device and a processor coupled to the storage device is provided. The storage device stores a program for controlling the processor, and the processor, being operative with the program, is configured to identify a portion of a retrieved web document that is displayed to a user. The identified portion includes at least a first boundary and a second boundary in a scrolling direction. The processor is further configured to select at least one object from the retrieved web document, and the at least one selected object is associated with a corresponding manipulation. The processor is configured to detect whether a portion of the at least one selected object falls between the first and second boundaries, and to perform the corresponding manipulation of the at least one selected object when the portion of the selected object falls between the first and second boundaries. 
     Other embodiments of the present invention relate to a computer-readable medium with stored instructions that, when executed by a processor, perform a method for manipulating objects in a web document. The method identifies a portion of a retrieved web document that is displayed to a user. The identified portion includes a first boundary and a second boundary in a scrolling direction. The method then selects at least one object from the retrieved web document, and the at least one selected object is associated with a corresponding manipulation. The method detects whether a portion of the at least one selected object falls between the first and second boundaries, and then performs the corresponding manipulation of the at least one selected object when the portion of the selected object falls between the first and second boundaries. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention. Further, the accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram of an exemplary computing environment within which embodiments of the invention may be practiced. 
         FIG.  2    is a diagram of an exemplary computer system, consistent with embodiments of the invention may be implemented. 
         FIGS.  3 A- 3 C  illustrate features of an exemplary web document that may be selectively viewed and manipulated, according to embodiments of the invention. 
         FIG.  4    is a flowchart of an exemplary method for manipulating objects within a web document, according to an embodiment of the invention. 
         FIG.  5    is a flowchart of an exemplary method for polling objects within a polling queue, according to an embodiment of the invention. 
         FIG.  6    is a flowchart of an exemplary method for selectively downloading objects associated with a retrieved web document, according to an embodiment of the invention. 
         FIG.  7    is a flowchart of an exemplary method for detecting objects visible in a retrieved web document, according to an embodiment of an invention. 
         FIG.  8    is a flowchart of an exemplary method for computing a position of an identified object within a web document, according to an embodiment of the invention. 
         FIG.  9    is a flowchart of an exemplary method for detecting objects visible in a retrieved web document, according to an additional embodiment of an invention. 
         FIG.  10    illustrates features of an exemplary web document that may be selectively viewed and manipulated according to embodiments of the invention. 
         FIG.  11    illustrates features of an exemplary web document that may be selectively viewed and manipulated according to embodiments of the invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Reference will now be made in detail to embodiments of the invention, examples of which are illustrated in the accompanying drawings. The same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     In this application, the use of the singular includes the plural unless specifically stated otherwise. In this application, the use of “or” means “and/or” unless stated otherwise. Furthermore, the use of the term “including,” as well as other forms such as “includes” and “included,” is not limiting. In addition, terms such as “element” or “component” encompass both elements and components comprising one unit, and elements and components that comprise more than one subunit, unless specifically stated otherwise. Additionally, the section headings used herein are for organizational purposes only, and are not to be construed as limiting the subject matter described. 
       FIG.  1    illustrates an exemplary computing environment  100  within which embodiments of the present invention may be practiced. In  FIG.  1   , web servers  162  and  164 , user computers  102  and  104 , and mobile device  112  are interconnected via a communications network  130 . These components may perform various operations including, for example, exchanging information, transmitting requests for web documents, such as web pages, and responding to requests by retrieving and providing web documents. Although computing environment  100  includes multiple user computers and mobile devices in communication with web servers  162  and  164 , persons of ordinary skill in the art will recognize that computer environment  100  may include any number of user computers, any number of mobile devices, any number of additional web servers, and any additional number of computers or servers without departing from the spirit or scope of the present invention. 
     Communications network  130  may represent any form or medium of digital data communication. Examples of communication network  130  include a local area network (“LAN”), a wireless LAN, e.g., a “WiFi” network, a wireless Metropolitan Area Network (MAN) that connects multiple wireless LANs, and a wide area network (“WAN”), e.g., the Internet. In the embodiments described herein, the Internet may include any publicly-accessible network or networks interconnected via one or more communication protocols, including, but not limited to, hypertext transfer protocol (HTTP) and transmission control protocol/internet protocol (TCP/IP). Moreover, communications network  130  may also include one or more mobile device networks, such as a GSM network or a PCS network, that allow mobile devices, such as mobile device  112 , to send and receive data via applicable communications protocols, including those described above. 
     Although not depicted in  FIG.  1   , web servers  162  and  164  may include a front end portion and a back end portion, which is disposed in communication with the front end portion. For example, the front end portion and the back end portion of web servers  162  and  164  may be incorporated into a hardware unit, for example, a single computer or a single server. In such an exemplary embodiment, the front end portion may be a software application, such as a web service, executing on web servers  162  and  164 . However, web servers  162  and  164  are not limited to such configurations, and, in additional embodiments, the front end portion may be executed on any computer or server separate from the back end portion without departing from the spirit of scope of the present invention. 
     User computers  102  and  104 , and additionally, web servers  162  and  164  and mobile device  112 , may represent any type of computer system capable of performing communication protocol processing.  FIG.  2    is an exemplary computer system  200 , according to an embodiment of the invention. Exemplary computer system  200  includes one or more processors, such as processor  202 . Processor  202  is connected to a communication infrastructure  206 , such as a bus or network, e.g., network  130  of  FIG.  1   . 
     Computer system  200  also includes a main memory  208 , for example, random access memory (RAM), and may include a secondary memory  210 . Secondary memory  210  may include, for example, a hard disk drive  212  and/or a removable storage drive  214 , representing a magnetic tape drive, an optical disk drive, CD/DVD drive, etc. The removable storage drive  214  reads from and/or writes to a removable storage unit  218  in a well-known manner. Removable storage unit  218  represents a magnetic tape, optical disk, or other storage medium that is read by and written to by removable storage drive  214 . As will be appreciated, the removable storage unit  218  can represent a computer readable medium having stored therein computer programs, sets of instructions, code, or data to be executed by processor  202 . 
     In alternate embodiments, secondary memory  210  may include other means for allowing computer programs or other program instructions to be loaded into computer system  200 . Such means may include, for example, a removable storage unit  222  and an interface  220 . An example of such means may include a removable memory chip (e.g., EPROM, RAM, ROM, DRAM, EEPROM, flash memory devices, or other volatile or non-volatile memory devices) and associated socket, or other removable storage units  222  and interfaces  220 , which allow instructions and data to be transferred from the removable storage unit  222  to computer system  200 . 
     Computer system  200  may also include one or more communications interfaces, such as communications interface  224 . Communications interface  224  allows software and data to be transferred between computer system  200  and external devices. Examples of communications interface  224  may include a modem, a network interface (e.g., an Ethernet card), a communications port, a PCMCIA slot and card, a wireless transmitter or card, etc. Software and data may be transferred via communications interface  224  in the form of signals  226 , which may be electronic, electromagnetic, optical or other signals capable of being received by communications interface  224 . These signals  226  are provided to communications interface  224  via a communications path (i.e., channel  228 ). Channel  228  carries signals  226  and may be implemented using wire or cable, fiber optics, an RF link, wireless transmissions, and other communications channels. In an embodiment of the invention, signals  226  comprise data packets sent to processor  202 . Information representing processed packets can also be sent in the form of signals  226  from processor  202  through communications path  228 . 
     The terms “storage device” and “storage medium” may refer to particular devices including, but not limited to, main memory  208 , secondary memory  210 , a hard disk installed in hard disk drive  212 , and removable storage units  218  and  222 . Further, the term “computer readable medium” may refer to devices including, but not limited to, a hard disk installed in hard disk drive  212 , any combination of main memory  208  and secondary memory  210 , and removable storage units  218  and  222 , which respectively provide computer programs and/or sets of instructions to processor  202  of computer system  200 . Such computer programs and sets of instructions can be stored within one or more computer readable media. Additionally or alternatively, computer programs and sets of instructions may also be received via communications interface  224  and stored on the one or more computer readable media. 
     Such computer programs and instructions, when executed by processor  202 , enable processor  202  to perform one or more of the computer-implemented methods described herein. Examples of program instructions include, for example, machine code, such as that code produced by a compiler, and files containing a high-level code that can be executed by processor  202  using an interpreter. 
     The computer-implemented methods described herein can also be implemented on a single processor of a computer system, such as processor  202  of system  200 . In another embodiment, computer-implemented methods consistent with embodiments of the invention may be implemented using one or more processors within a single computer system, and additionally or alternatively, these computer-implemented methods may be implemented on one or more processors within separate computer systems linked via a network. 
     In the embodiments described herein, a user may request a web document, for example, a web page, by entering a URL into a web browser executing on a user device, such as user computer  102  or mobile device  112  of  FIG.  1   . Upon entry of that URL, the web browser determines an appropriate transfer protocol and requests the web document from a corresponding server computer, e.g., web servers  162  and/or  164 , using the determined protocol. The server(s) may then transmit the requested web document to the user device, which receives the retrieved web document and which generally stores the retrieved web document in its entirety. 
       FIGS.  3 A,  3 B, and  3 C  illustrate features of an exemplary web document  300  that may be selectively viewed and manipulated, according to embodiments of the invention. In an embodiment, web document  300  can represent a web page in HTML format, a web page in XHTML format, or a web page in additional or alternate format appropriate to a user&#39;s web browser. Consistent with embodiments of the invention, web document  300  is not limited to web pages, and in additional embodiments, web document  300  may represent any of a number of retrievable documents or data, including, but not limited to email attachments in HTML or other formats, and XML-enriched documents, for example. 
     As depicted in  FIG.  3 A , web document  300  may include one or more objects, such as objects  302 ,  304 , and  306  that, for example, may be associated with plain text and hyperlinks. Further, web document  300  may also include one or more objects, such as objects  307 ,  308 ,  310 ,  312 ,  314 , and  316 , that are associated with media content. In an embodiment, the media content may represent an image or an embedded link to streaming video, for example, from an additional web site. Further, for example, the media content may represent an embedded executable script, including, but not limited to, an executable JavaScript and an executable AJAX script. However, web document  300  is not limited to objects associated with such exemplary content, and in additional or alternate embodiments, web document  300  may include any number objects associated with any variety of content, without departing from the spirit or scope of the invention. 
     In the example  FIG.  3 A , web document  300  may be characterized by a body height  380  that, for example, is expressed as a number of pixels measured from an upper edge  300 A of web document  300 . Further, a position of each object within web document  300  may be characterized in terms of an object height and an object offset. In an embodiment, the object offset represents a displacement between an upper edge of an object and upper edge  300 A of web document  300 . 
     For example, and as depicted in  FIG.  3 B , a position of object  310  may be determined by object height  330  and an object offset  340 , which represents a displacement between upper edge  310 A of object  310  and upper edge  300 A of web document  300 . Further, for example, a position of object  316  within web document  300  may be determined by an object height  336  and an object offset  346 , which represents a displacement between upper edge  316 A of object  316  and upper edge  300 A of web document  300 . Further, although not depicted in  FIG.  3 B , similar object heights and object offsets may used to establish a position of each of objects  302 ,  304 ,  306 ,  307 ,  308 ,  312  and  314 , and additionally, any other object present within web document  300 . 
     In an embodiment, body height  380  of web document  300  may be substantially larger than a corresponding height of a viewport, such as a viewport of a web browser or other appropriate executable program that displays web document  300  to a user. The viewport of the web browser viewport represents an area provided by the web browser through which web document  300  is displayed to the user. 
     A size of a browser viewport may be limited by a corresponding size of a display associated with the user&#39;s device, e.g., a monitor or display screen. In such instances, the size of the viewport may be reduced by one or more toolbars and/or scrollbars. Further, some operating systems support multiple virtual display screens that, for example, allow the browser viewport to be larger than a corresponding display screen of the user&#39;s device. 
     Dimensions of the browser viewport, e.g., a width and height, may be determined using, for example, JavaScript properties. The selection of an appropriate JavaScript property may depend on, for example, the user&#39;s web browser and on the web document viewed through the viewport. Using many conventional web browsers, the height and width of the browser viewport may be determined, respectively, by the “innerHeight” and “innerWidth” properties. 
     However, in additional embodiments, the user&#39;s web browser and the displayed document may require an application of additional or alternate JavaScript property to determine the height and width of the browser viewport. For example, the viewport width may be determined using the “documentElement.clientWidth” and the “body.clientWidth” properties of JavaScript, and the viewport height may be determined using the “documentElement.clientHeight” and “body.clientHeight” properties of JavaScript. 
     For example, in  FIG.  3 C , a viewport  390  of the user&#39;s web browser may be able to display only a subset of web document  300 , i.e., objects  302 ,  304 ,  310 , and  312  in their entirety and portions of objects  306  and  308 . In order to view the remainder of objects  306 ,  307 , and  308 , and in order to view objects  314  and  316 , the user must scroll through web document  300  along a scrolling direction  370  to re-position viewport  390  over one or more additional portions of web document  300 . 
     A position of viewport  390  along scrolling direction  370  may be characterized in terms of a height  394  and in terms of an offset  392 . In an embodiment, offset  392  identifies a current scroll position within web document  300 , and may be defined as a displacement, measured along scroll direction  370 , between an upper boundary  390 A of viewport  390  and upper boundary  300 A of web document  300 . Further, for example, both height  394  and offset  392  may be expressed in terms of a number of pixels. 
     Web users often download and store a requested web document, e.g., a web page, in its entirety before viewing that web document. Although these requested web documents may include static and unchanging content, a requested web pages may also feature content configured to be refreshed periodically, such as embedded advertisements. As such, not only must the entire web document be initially downloaded and stored prior to viewing a portion of that web document, but the user&#39;s web browser often submits additional requests to refresh previously-stored content, regardless of whether the user views the previously-stored content. 
       FIG.  4    illustrates an exemplary method  400  for selectively manipulating objects within a stored web document, according to an embodiment of the invention. In step  402 , a portion of a stored web document is displayed to a user through a viewport of a web browser, e.g., viewport  390  of  FIG.  3 C . In an embodiment, the stored web document may represent a web page that includes one or more objects, each of which are downloaded and stored in their entirety. For example, these objects may represent one or more digital images, streaming video, Flash media content, and executable scripts (e.g., JavaScript or AJAX). Additional or alternate content can also be provided, as will be apparent to a person of skill in the art without departing from the spirit or scope of the invention. 
     In step  404 , an object of the web document is selected that is associated with a corresponding action or manipulation. For example, the object selected in step  404  may represent an advertisement within the stored web document that is scheduled to be refreshed by the user&#39;s web browser. However, the selected object is not limited to refreshable advertising content, and in additional embodiments, the selected object may be associated with any of a variety of downloadable content, including, but not limited to still images, streaming media, and Flash media. Further, the particular action is not limited the retrieval of online content, and additionally or alternatively, the corresponding manipulation may represent an execution of an corresponding script or function, e.g., in JavaScript or AJAX format. 
     In step  406 , a determination is made as to whether the selected object is currently visible to the user through the viewport of the user&#39;s web browser. For example, as part of step  406 , the selected object may be determined to be “visible” to the user when the selected object falls entirely within the viewport of the user&#39;s web browser, i.e., when the boundaries of the selected object fall entirely between the boundaries of the viewport. 
     In an additional embodiment, a less restrictive definition of “visibility” is used as part of step  406 . For example, as part of step  406 , the selected object may be deemed to be “visible” to the user when any portion of the selected object is visible to the user through the viewport, i.e., when at least a portion of the selected object falls between the boundaries of the viewport. 
     Additionally, or independently, step  406  may also deem the selected object visible to the user when at least a portion of that selected object falls within a threshold detection distance of the boundaries of the viewport. For example, step  406  may artificially expand the boundaries of the viewport according to the threshold detection distance, and may deem the selected object as being visible to the user when the selected object falls entirely within the expanded boundaries of the viewport. Further for example, step  406  may deem the selected object as visible to the user when any portion of that selected object falls within the expanded boundaries of the viewport. In such an embodiment, step  406  may not only identify objects within the web document that are currently visible to the user, but may also identify objects that are likely to become visible in response to an action by the user, for example, in response to scrolling through the web document. 
     If it is determined that the selected object is visible to the user (step  406 ; Yes), then the process proceeds to step  408  to perform a corresponding manipulation associated with the selected object. For example, step  408  may refresh the downloaded content associated with the selected object by requesting and retrieving corresponding updated content from a web server, e.g., web servers  162  and  164  of  FIG.  1   . 
     However, step  408  is not limited to refreshing downloaded content, and in additional embodiments, step  408  may execute a corresponding script or function associated with the selected object. For example, step  408  may execute a JavaScript that embeds a Flash media player in a position within the web document corresponding to the selected object. 
     Once step  408  performs the corresponding manipulation of the selected object, step  410  determines whether additional objects in the web document require action or manipulation. For example, step  410  may determine whether downloaded content associated with one or more additional objects in the stored web document need to be refreshed. In such an embodiment, method  400  passes from step  410  back to step  404 , which selects an additional object for processing. However, if it is determined that no additional objects within the stored web document require additional action or manipulation (step  410 ; No), then method  400  is complete and finishes at step  414 . 
     Referring again to step  406 , if it is determined that the selected object is not currently visible to the user (step  406 ; No), then no corresponding manipulation of the selected object is performed, and at step  412  the selected object is added to a polling queue for additional analysis in response to user action, e.g., in response to the user scrolling through an additional portion of the web document. In an embodiment, the polling queue associated with step  412  includes one or more objects of the web document that are not visible through the viewport at a current scroll position. For example, in reference to  FIG.  3 C , step  412  may add objects  314  and  316  to the polling queue, since these object may not visible to the user through viewport  390 . As the user scrolls through the web document, and the position of viewport  390  translates through the web document, objects within the polling queue are “polled” to detect whether the polled objects are visible to the user and, once visible, to perform a manipulation of each visible “polled” object. 
     In an embodiment, step  412  may add an identifier associated with the selected object to the polling queue and may specify a threshold distance for the detection of visible polled objects. Further, in an additional or independent embodiment, step  412  may also specify a call-back function associated with the selected object, and step  412  may add this call-back function to the polling queue. In an embodiment, the call-back function, e.g., a JavaScript or AJAX function, is associated with the polled object and is executed once that polled object is deemed visible to the user. 
     For example, a call-back function added to the polling queue may represent a JavaScript that embeds a Flash media player into the web document at a position in the web document corresponding to the polled object. In such an embodiment, once the polling process deems that the polled object is visible to the user, the call-back function is executed to embed the Flash player. 
     Once the selected object is added to the polling queue in step  412 , method  400  passes to step  410  to determine whether additional objects in the stored web document require manipulation. As described above, if step  410  determines that additional objects in the web document require manipulation, e.g., the refreshment of stored online content, then step  404  selects an additional object for processing. However, if step  410  determines that no additional objects within the stored web document require additional, then method  400  is complete at step  414 . 
     In contrast to conventional systems and methods for web-based document retrieval, exemplary method  400  only initiates additional action related to an object in the stored web document, e.g., downloading additional content or executing a script or function, when that object is visible to the user through the viewport of the user&#39;s web browser. Although the user experiences a communications overhead when downloading and storing the requested web document, the exemplary embodiment of method  400  can reduce additional overhead resulting from the manipulation of a stored object not currently visible to the user through the user&#39;s browser viewport. 
       FIG.  5    illustrates an exemplary method  500  for polling objects stored within a polling queue, according to an embodiment of the invention. In an embodiment, method  500  may be implemented as part of step  412  of  FIG.  4    to poll those selected objects that are added to the polling queue. However, in additional embodiments, method  500  may be independently employed to poll objects within, for example, a pre-existing polling queue or any additional or alternate set of objects in a web document. 
     In  FIG.  5   , step  502  determines that a user has scrolled to a new position within a web document, i.e., that the current scroll position has changed, and identifies that new scroll position. Step  504  then initiates the polling process by selecting one of the polled objects from within the polling queue for further processing and analysis. 
     Step  506  then determines whether the polled object is now visible to the user at the new scroll position. As described above in reference to step  406  of  FIG.  4   , step  506  may deem the selected polled object “visible” to the user when the polled object falls entirely within the viewport of the user&#39;s browser, i.e., when the boundaries of the selected object falls entirely between the boundaries of the viewport. However, step  506  may incorporate a less restrictive definition of “visibility.” For example, step  506  may deem the selected object “visible” to the user when any portion of that selected object is visible to the user through the viewport, i.e., at least a portion of the selected object falls within the boundaries of the viewing screen. Additionally, or independently, step  506  may also deem the selected object as visible to the user when at least a portion of that selected object falls between a threshold detection distance of the boundaries of the viewport, as described above in reference to  FIG.  4   . 
     If step  506  determines that the polled object is visible to the user through the newly-positioned viewport, then step  508  performs a corresponding manipulation of the polled object. For example, the corresponding manipulation may include requesting updated content from a web sever to refresh previously-stored content associated with the polled object. 
     Additionally or independently, step  508  may execute a call-back function associated with the polled object when step  506  deems the polled object visible to the user. For example, the call-back function may represent a JavaScript that embeds a Flash media player into the web document. However, the call-back function is not limited to such executable scripts, and in additional embodiments, step  508  may execute any of a number of appropriate call-back functions expressed in JavaScript format, AJAX format, or in any additional or alternate format, without departing from the spirit and scope of the present invention. 
     Once step  508  performs the corresponding manipulation, then step  510  removes the polled object from the polling queue. Step  512  then determines whether the polling queue includes additional objects. If step  512  determines that the polling queue includes no additional objects, i.e., that the polling queue is empty, then method  500  is complete in step  514 . In such an embodiment, the polling process awaits the addition of one or more additional objects to the polling queue through, for example, the processes described above in reference to step  412  of  FIG.  4   . 
     However, if step  512  determines that the polling queue is not empty, then step  516  determines whether these remaining objects have been polled at the new scroll position. If additional objects require polling at the new scroll position, then method  500  passes back to step  504 , which selects an additional object from the polling queue. If, however, step  516  determines that all object in the polling queue have been polled at the new scroll position, then method  500  is complete in step  518 . In such an embodiment, the polling process remains dormant until the user scrolls through the web document, thereby changing the scroll position and the position of the viewport within the web document, at which time the polling process  500  is re-initialized in steps  502  and  504 . 
     Referring back to step  506 , if the selected polled object is not visible to the user, then method  500  passes to step  520 , which maintains the selected object within the polling queue for further processing, for example, when the scroll position changes. Method  500  then passes to step  516 , which determines whether additional objects remain to be polled at the current scroll position. If additional objects require polling, then method  500  passes back to step  504 , which selects an additional object from the polling queue. If, however, step  516  determines that all object in the polling queue have been polled, then method  500  is completed in step  518 , as described above. 
     The polling process described above in reference to the exemplary embodiments of  FIGS.  4  and  5    not only perform manipulations (e.g., refreshing content and executing scripts) associated with a currently-visible object, but these polling processes may also provide a mechanism for automatically manipulating additional objects in the web document when those objects become visible to the user. For example, the exemplary methods of  FIGS.  4  and  5    may allow for an automatic execution of call-back functions related to objects as these objects become visible, thereby reducing unnecessary communications overhead related to manipulating objects not actually visible to the user. 
     In the embodiments of  FIGS.  4  and  5   , the requested web document is downloaded by the user device and stored at that user device in its entirety, and stored objects are selectively manipulated when these objects become visible to the user. However, as described above, only a small fraction of users view a requested web document in its entirety. Thus, while the exemplary methods of  FIGS.  4  and  5    may reduce additional communications overhead associated with manipulating objects not visible to the user, these exemplary method may still require the user to initially download the entire requested web document. 
       FIG.  6    illustrates an exemplary method  600  for selectively downloading objects associated with a retrieved web document, according to an embodiment of the invention. In an embodiment, and in contrast to the exemplary methods of  FIGS.  4  and  5   , method  600  retrieves a requested web document from a web server, and only downloads those objects that would be visible to a user at a current scroll position. In such an embodiment, method  600  can reduce both an overall download time and a connection bandwidth required to obtain and view a requested web document. 
     In step  602 , a user device (e.g., user computer  102  or mobile device  112  of  FIG.  1   ) retrieves a requested web document from a web server (e.g., web servers  162  and  164  of  FIG.  1   ). In an embodiment, the received web document may represent a web page in HTML or XHTML format. However, the retrieved Web document is not limited to such web pages, and in additional embodiments, the user device may a requested a web document in any number of additional or alternate appropriate forms, without departing from the spirit or scope of the present invention. 
     Upon receipt of that requested web document, step  604  processes the received web document to identify one or more objects in the retrieved web document prior to downloading or otherwise manipulating these objects. In an embodiment, step  604  may identify the one or more objects based on a HTML tag associated with each of the one or more objects. For example, step  604  can identify each object in the retrieved web document having a HTML tag corresponding to an embedded image. In additional embodiments, step  604  may also identify each object in the retrieved web document associated with an executable script, including, but not limited to, scripts in JavaScript or AJAX format, e.g., a script that embeds a Flash media player into the retrieved web document. 
     Furthermore, the processing of step  604  is not limited to identifying objects of a single type, e.g., images or functions. For example, step  604  may be configured to identify any combination of one or more types of objects positioned within the received web document. In such embodiments, a web developer may configure the processing of step  604  to identify those objects that are require substantial time and/or bandwidth to load, while allowing less time- and bandwidth-consuming objects to be immediately downloaded at the user device. 
     Moreover, step  604  is not limited to identifying only a subset of the objects in the retrieved web document. In additional embodiments, step  604  may be configured to identify each object in the retrieved web document, regardless of object type, before downloading these identified objects. 
     In step  606 , one of the identified objects is selected for additional processing. Step  608  subsequently detects whether the selected object is visible to the user through a viewport, e.g., viewport  390  of  FIG.  3 C , of a user&#39;s web browser at a current scroll position. In an embodiment, step  608  may determine that the selected object is visible through the viewport if that selected object falls entirely within the boundaries of the viewport. For example, and in reference to  FIG.  3 C , step  608  may determine that objects  302 ,  304 ,  310  and  312  are visible to since each of these objects falls entirely within the boundaries of viewport  390 . 
     However, step  608  is not limited to such definitions of object visibility, and in an additional embodiment, the detection of step  608  may incorporate a less stringent definition of object visibility. For example, step  608  may determine that the selected object is visible to the user if any portion of that selected object falls within the boundaries of the viewport. For example, and in reference to  FIG.  3 C , step  608  may determine that objects  302 ,  304 ,  310 , and  312  are visible to the user, as each falls entirely within the boundaries of the viewport, and additionally, that objects  306  and  308  are visible since a portion of these objects fall within the viewport. 
     Further, step  608  may determine that the selected object is visible to the user if at least a portion of that selected object falls within a threshold detection distance of the boundaries of the viewport. In such an embodiment, the upper and lower boundaries of the viewport may be displaced by a distance equivalent to the threshold detection distance to form “expanded” boundaries, thereby creating an “effective” viewing area that incorporates both objects present visible to the user, and objects that may soon become visible to the user when the user scrolls through the web document. 
     The threshold detection distance may be specified by the user, or alternatively, the threshold detection distance may be based on a pre-determined default distance established, for example, by the web developer. In such exemplary embodiments, the threshold detection distance and default distance may be expressed in pixels, or alternatively, in any other appropriate unit of measure without departing from the spirit of scope of the present invention. 
     If step  608  determines that the selected object is “visible” to the user, i.e., entirely visible or partially visible, then a corresponding manipulation is performed on the selected object in step  610 . For example, if the selected object were an image, then the image corresponding to the selected object would be downloaded from the web server and stored locally. The downloaded image could then be displayed using the web browser as an embedded image within the web document. 
     Moreover, in an additional embodiment, step  610  may execute a function associated with the selected object to embed, for example, multimedia content, into a position within the web document corresponding to the selected object. For example, the function may represent a script, e.g., in JavaScript or AJAX format, that embeds a Flash Media Player into the position within the web document corresponding to the selected object. However, the function is not limited to such exemplary functionalities, and in additional embodiment, the function may represent an executable script in any additional or alternate format, as would be apparent to one of skill in the art. 
     Once the corresponding manipulation has been performed in the selected object in step  610 , step  612  determines whether additional objects require processing. If no additional objects require processing in step  612 , then the exemplary method is complete in step  614 . In such an embodiment, method  600  waits for the user to scroll through the web document, thereby changing the current scroll position in the web document and changing a position of the viewport. However, if step  612  determines that additional objects require processing, exemplary method  600  passes back to step  606 , which selects an additional object for processing. 
     If step  608  determines that the selected object is not currently visible to the user, then method  600  passes to step  616 , which stores a source of the selected object as a temporary variable, e.g., a temporary Java property of that selected object. Step  618  then replaces the source of the selected object with a blank placeholder that temporarily blocks the download of that selected object. 
     In an embodiment, the replacement in step  618  may depend on both a type of the selected object, e.g., an image, and on a web browser of the user. For example, if the selected object were an image, then step  618  could replace the source of the selected object with a blank image, for example, when the user&#39;s web browser is a Firefox web browser, and additionally or alternatively, step  618  could replace the source of the selected object with a blank character string, for example, when the user&#39;s web browser is Internet Explorer. However, step  618  is not limited to such exemplary replacements, and in additional embodiments, step  618  may replace the source of the selected object with any additional or alternate placeholder to block the download of the selected object, without departing from the spirit or scope of the invention. 
     Once the download of the selected object is blocked by steps  616  and  618 , the selected object is added to a polling queue in step  620  for future action once the selected function becomes visible within the viewport. For example, step  620  may incorporate the exemplary polling processes described above in reference to  FIG.  5    to process the selected objects within the polling queue as the user scrolls through the received web document. For example, the polling process of step  620  detects which, if any, of the queued objects becomes visible to the user through as the user scrolls through the web document, and in response to this detection, the polling process would replace the placeholder with the true source of the newly-visible object and would perform a corresponding manipulation on the newly-visible object. 
     Once the selected object is added to the polling queue, method  600  then passes to step  612 , which determines whether additional objects require processing. If step  612  determines that no additional objects require processing, then method  600  is complete in step  614 . However, if step  612  determines that additional object require processing, then method  600  passes back to step  606 , which selects an additional object for processing. 
     In the embodiments described above, method  600  may download objects associated with a received web document when those objects are visible to the user. Therefore, in contrast to conventional systems and methods of web-based document retrieval, exemplary method  600  dynamically downloads and manipulates content associated with a received document in response to user demand, e.g., when the content is visible to the user. As such, exemplary method  600  can reduce a waiting time and a connection bandwidth necessary to load a retrieved web document, as an amount of data requested by the user&#39;s web browser is linked directly to the user&#39;s viewing preferences. 
       FIG.  7    illustrates an exemplary method  700  for detecting visible objects in a retrieved web document, according to an embodiment of an invention. In an embodiment, method  700  may be incorporated into any of the exemplary methods described above in reference to  FIGS.  4 - 6    to detect whether an identified object or objects are visible to a user through a viewport of a web browser. However, the exemplary processes of  FIG.  7    are not limited to such implementations, and in additional embodiments, method  700  may be implemented independently or in conjunction with any additional process, without departing from the spirit or scope of the invention. 
     In  FIG.  7   , step  702  identifies an object from within a retrieved web document, e.g., a HTML web page. In an embodiment, the identified object may represent an image embedded within the web document, and additionally or alternatively, the identified object may also reference a function that, for example, embeds a Flash media player into a position in the web document associated with the identified object. For example, such function can be defined in JavaScript format, in AJAX format, or in any additional or alternate format appropriate to the user&#39;s web browser. 
     Further, step  702  also identifies one or more detection parameters, including, but not limited to a threshold detection distance. In an embodiment, the identified threshold detection distance may be applied to “expand” each boundary of the viewport of the user&#39;s web browser to allow the detection of objects that that fall within the specified threshold detection distance of the viewport. In an embodiment, the threshold detection distance may be specified as a non-zero number of pixels. However, in an additional embodiment, the user may specify a zero-pixel threshold value, thereby limited the detection of object that at least partially fall within the original boundaries of the viewport. 
     Step  704  then determines one or more parameters associated with the retrieved web document. For example, step  704  may determine a dimension of the web document in the scrolling direction, i.e., a body height of the web document (e.g., body height  360  of web document  300  of  FIG.  3 A ). 
     Step  704  also determines one or more parameters associated with the viewport of the user&#39;s web browser. For example, step  704  may determine a height associated with the viewport of the user&#39;s web browser (e.g., height  394  of viewport  390  in  FIG.  3 C ) and a current scroll position that defines a position of the viewport (e.g., offset  392  of viewport  390  of  FIG.  3 C ) within the retrieved web document. 
     In an embodiment, the parameters determined in step  704  may be computed using one or more JavaScript properties. For example, the body height of the web document may using the “offsetHeight” property of JavaScript. In such an embodiment, the application of the “offsetHeight” property to the web document would return a total linear height of the web document, measured in pixels. 
     Further, for example, step  704  may employ one or more additional JavaScript properties to obtain a height of the viewport of the user&#39;s web browser. For example, an application of the “innerHeight” property to a variable representing the viewport returns a height of the viewport in pixels, including, for example, a height of a horizontal scroll bar associated with the viewport. 
     However, the determination of the height of the user&#39;s browser viewport is not limited to the “innerHeight” property. For example, the user device may be executing a web browser that fails to support the “innerHeight” property. In such embodiments, step  704  may determine the height of the user&#39;s browser viewport using any additional or alternate property of JavaScript, including, but not limited to, the “body.clientHeight” property and the “documentElement.clientHeight” property. 
     Step  704  may also employ one or more one or more JavaScript properties to compute the current scroll position within the web document. For example, the scroll position may be determined by applying the “documentElement.scrollTop” property to a variable representing the web document in order to determine the scroll position in pixels. 
     However, as described above, not all web browsers support the functionality of the “documentElement.scrollTop” property. In such embodiments, step  704  may employ one or more JavaScript properties, either alone or in combination, to compute the scroll position in a manner compatible with most web browsers. For example, step  704  may apply one or more of the “pageYOffset” property and the “body.scrollTop” property to a variable associated with a web document to determine the scroll position within the web document. 
     Step  706  then determines one or more parameters associated with the identified object, including, but not limited to, a height of the identified object (e.g., height  320  of object  310  of  FIG.  3 B ) and a corresponding offset associated with the identified object (e.g., offset  330  of object  310  of  FIG.  3 B ). As described above in reference to  FIG.  3 B , the corresponding offset may be defined as a displacement between an upper edge of the identified object and an upper edge of the web document. Further, as described above, a combination of the object height and object offset may define a position of the identified object in a scrolling direction of the retrieved web document. 
     In an embodiment, step  706  may apply JavaScript properties, including, but not limited to, the “offsetHeight” property described above, to compute the height in pixels of the identified object. Moreover, step  706  also computes the position of the identified object within the received web document. However, in contrast to the scroll position described above, the position of the identified object within a web document remains unchanged unless additional information is added to the web document, thereby changing the body height of the web document. 
     In an embodiment, step  706  leverages these properties of the object position in order to reduce a number of computational cycles necessary to determine whether the identified object is visible through the viewport. In such an embodiment, step  706  recycles a previously-computed position of the identified object, if such a previously-computed position exists, unless a height of the received web document has changed since the last computation. 
       FIG.  8    illustrates an exemplary method  800  for computing a position of an identified object within a web document, according to an embodiment of the invention. By way of example, the method of  FIG.  8    may be incorporated into step  706  of  FIG.  7   . However, in an additional embodiment, exemplary method  800  may be implemented or otherwise incorporated into a process independently of step  706 , without departing from the spirit or scope of the invention. 
     Step  802  determines whether a position of the identified object has been previously computed and cached for future use. If step  802  determines that a cached version of the position exists, then method  800  passes to step  804 , which determines whether a height of the web document that includes the identified object has changed since the position of the identified object was computed. If step  804  determines that the height of the web document is unchanged, the step  806  uses the cached position as the position of the identified object, and method  800  is completed in step  812 . In an embodiment, step  806  returns the cached position of the identified object to step  706  of  FIG.  7    for additional processing. 
     However, if step  804  determines that the height of the web document has changed since the cached position was computed or, alternatively, if step  802  determines that no cached position has been computed, then step  808  computes the position of the identified object. In an embodiment, step  808  may compute the position of the identified object within the web document, e.g., displacement  320  of object  310  in  FIG.  3 B , based on a relative position of each object positioned in the web document above the identified object. For example, step  808  can loop through each object in the web document above the identified object and compute a relative position of each object using the JavaScript property “offsetTop.” These relative positions may then be summed to yield the position of the identified object within the web document. 
     The computed position of the identified object is subsequently cached for future access in step  810 , along with, for example, a height of the web document at the time of computation, and method  800  is completed in step  814 . As described above, the computed position of the identified object may be returned to step  706  of  FIG.  7    for additional processing. 
     Referring back to  FIG.  7   , once the parameters related to the viewport and the received web document are computed in step  704 , and the parameters related to the identified object are computed in step  706 , step  708  then determines whether a lower edge of the identified object (e.g., edge  310 B of object  310  in  FIG.  3 B ) falls above an upper edge of the viewport (e.g., upper edge  390 A in  FIG.  3 C ). In an embodiment, the upper boundary of the viewport used in the determination of step  708  may be expanded upward to account for the identified threshold detection distance, as described above. 
     For example, step  708  may test whether the following expression is satisfied: 
       lower_edge_identified_object&lt;upper_edge_viewing_window,   (1)
 
     wherein: 
       lower_edge identified_object=object_position+object_height; and   (2)
 
       upper_edge_viewing_window=scroll_position−threshold distance.   (3)
 
     In Equations (1)-(3), lower edge identified object represents a position of the lower edge of the identified object measured relative to the upper edge Of the web document, and upper_edge_viewing_window represents a scroll position within the web document adjusted to account for the threshold distance. Further, object_position and object_height in Equation (2) represent, respectively, the position of the upper edge of the identified object within the web document and the height of the identified object. In an embodiment, these values may be determined using the techniques described above in reference to step  706 . In Equation (3), scroll_position represents a current scroll position within the web document, as described above in reference to step  704 , and threshold_distance represents the threshold detection distance identified in step  702 . 
     If step  708  determines that Equation (1) is satisfied, then the lower edge of the identified object falls above an upper edge of the viewport, as adjusted to account for the threshold distance. Accordingly, step  710  then determines that the identified object is positioned above the user&#39;s browser viewpoint, and that the identified object is not visible to the user. Method  700  is then completed in step  716 . 
     However, if step  708  determines that Equation (1) is not satisfied, then step  712  determines whether the upper edge of the identified object (e.g., edge  310 A of object  310  in  FIG.  3 B ) falls below the lower edge of the viewport (e.g., edge  390 B of viewpoint  390  in  FIG.  3 C ). Similar to the embodiment described above, the lower boundary of the viewport used in the determination of step  712  may be displaced to account for the identified threshold detection distance. In such an embodiment, step  712  may test whether the following expression is satisfied: 
       upper_edge_identified_object&gt;lower_edge_viewing_window,   (4)
 
     wherein: 
       upper_edge_identified_object=object_position; and   (5)
 
       lower_edge_viewing_window=scroll_position+viewing_window_height+threshold_distance.   (6)
 
     In Equations (4)-(6), upper_edge_identified_object represents an upper edge of the identified object measured relative to the upper edge of the web document, and lower_edge_viewport represents a lower edge of the viewport, which may be expanded to account for the threshold detection distance. Further, in Equation (6), viewing_window_height represents the height, in pixels, of the user&#39;s browser viewport, as described above in reference to step  704 . 
     If step  712  determines that Equation (8) is satisfied, then the upper edge of the identified object is positioned below the lower edge of the user&#39;s browser viewport. Therefore, no portion of the identified object falls within the threshold distance of the viewport, and method  700  passes to step  710 , which determines that the identified object is not visible to the user through the viewport of the user&#39;s web browser. 
     However, if step  712  determines that Equation (8) is not satisfied, then at least at least a portion of the identified object falls within the boundaries of the user&#39;s browser viewport, which may have been expanded to account for the threshold detection distance. Accordingly, step  714  determines that the identified object is visible to the user through the viewport of the user&#39;s web browser, and method  700  is completed in step  716 . 
     In the embodiment described in  FIG.  7   , an identified object is “visible” to the user if any portion of that identified object falls within the threshold distance of the viewport. However, the detection processes of  FIG.  7    are not limited to such a definition of a “visible” object. 
       FIG.  9    illustrates an exemplary method  900  for detecting objects in a web document that are entirely visible through a user&#39;s browser viewport, according to an embodiment of the invention. In contrast to the embodiment of  FIG.  7   , method  900  deems an identified object as “visible” if the identified object falls entirely within the edges of the user&#39;s browser viewport, which, as described above, may be expanded to account for the threshold detection distance. 
     In  FIG.  9   , step  902  identifies an object from within a retrieved web document, e.g., a HTML web page. As described above, the identified object may represent an image embedded within the web document, and additionally or alternatively the identified object may also reference a function that, for example, embeds a Flash media player into a position in the web document associated with the identified object. Such functions may be defined in JavaScript format, in AJAX format, or in additional format appropriate to the user&#39;s web browser. 
     Further, step  902  also identifies one or more detection parameters, including, but not limited to a threshold detection distance. As described above in reference to  FIG.  7   , the identified threshold detection distance may be applied to “expand” the edges of the user&#39;s browser viewport to allow the detection of objects that that fall within the specified threshold detection distance of that viewport. 
     One or more parameters related to the received web document and the viewport of the user&#39;s web browser are then determined in step  904 . Similar to the methods described above in reference to  FIG.  7   , step  904  may compute a body height of the web document (body_height), a height of the browser viewport (viewport_height), and a current scroll position within the web document, (scroll_position). In an embodiment, step  904  may compute the parameters using one or more JavaScript properties, as described above in reference to step  704  of  FIG.  7   . 
     Step  906  then determines one or more parameters related to the identified object, including, but not limited to, a height associated with the identified object (object_height) and a corresponding offset associated with the identified object (object_position). In an embodiment, step  906  may compute the height associated with the identified object through the application of one or more JavaScript properties, as described above in reference to step  706  of  FIG.  7   . Further, as described above in reference to step  706  of  FIG.  7   , the offset associated with the identified object, i.e., the object position within the web document, may be computed using a cached value of the position unless a height of the web document is changed. 
     Step  908  then determines whether a lower edge of the identified object falls within the lower edge of the viewport. Similar to the embodiments of  FIG.  7   , the lower boundary of the viewport may expanded to account for the identified threshold detection distance. For example, step  908  may test whether the following expression is satisfied: 
       lower_edge_identified_object&gt;lower_edge_viewing_window.   (7)
 
     In Equation (7), lower_edge_identified_object represents a position of the lower edge of the identified object measured relative to the upper edge of the web document, and lower_edge_viewport represents a lower edge of the viewport, which may be expanded to account for the threshold detection distance. In an embodiment, lower_edge_identified_object and lower_edge_viewport may be calculated using the techniques outlined above in reference to Equations (2) and (6), respectively. 
     If step  908  determines that Equation (7) is satisfied, then the lower edge of the identified object falls below the expanded lower edge of the viewport. Therefore, in step  910 , the identified object deemed is not visible to the user through the viewport of the user&#39;s web browser, since at least a portion of the identified object falls below of the expanded lower edge of the viewport, and method  900  is completed in step  916 . 
     However, if step  908  determines that Equation (7) is not satisfied, then step  912  determines whether the upper edge of the identified object falls within the upper edge of the viewport. Similar to the embodiment of  FIG.  7   , the upper boundary of the browser viewport may be expanded upward in step  912  to account for the identified threshold detection distance. For example, step  912  may test whether the following expression is satisfied: 
       upper_edge_identified_object&gt;upper_edge_viewport.   (8)
 
     In Equation (8), upper edge identified object represents an upper edge of the identified object measured relative to the upper edge of the web document, and upper_edge_viewport represents a scroll position within the web document adjusted to account for the threshold distance. In an embodiment, upper_edge_identified_object and upper_edge_viewport may be calculated using the techniques outlined above in reference to Equations (3) and (5), respectively. 
     If step  912  determines that Equation (8) is satisfied, then the upper edge of the identified object falls above the expanded the upper edge of the viewport. Accordingly, method  900  then passes back to step  910 , which determines that the identified object is not visible, since at least a portion of the identified object falls above of the expanded upper edge of the viewport. 
     However, if step  912  determines that Equation (8) is not satisfied, then upper edge of the identified object falls below the expanded upper edge of the viewport. Further, as step  908  determined that the lower edge of the identified object falls above the expanded lower edge of the viewport, the identified object falls entirely within the boundaries of the viewport, as expanded to account for the threshold detection distance. Step  914  then deems the identified object to be visible to the user through the viewport, and method  900  is completed in step  916 . 
     The embodiments of  FIGS.  7  and  9    are described in terms of a non-zero threshold detection distance, i.e., the upper and lower edges of the viewport are effectively “expanded” to account for the presence of the non-zero threshold detection distance. However, the exemplary methods of  FIGS.  7  and  9    are not limited to any particular threshold detection distance, and in additional embodiments, the threshold detection distances described above may be established to any non-zero value, or alternatively, may be set to zero, without departing from the spirit of scope of the present invention. 
     In an embodiment characterized by a zero threshold detection distance, any manipulation of objects outside of the user&#39;s browser viewport in anticipation of future scrolling by the user would be minimized, thereby further reducing the time and connection bandwidth required to load the presently-viewed content. Such an embodiment may be especially suited to those users who rarely view a substantial portion of a received web document, e.g., users of a search engine. 
     Further, in an embodiment, the exemplary processes of  FIGS.  7  and  9    may be used to detect a visibility of an object as a user scrolls through a web document, i.e., whether the object is visible through the user&#39;s browser viewport at the user&#39;s current scroll position. However, the exemplary processes of  FIGS.  7  and  9    are not limited to detecting the visibility of an object in response to the user&#39;s scrolling through the web document. In additional embodiments, the exemplary processes of  FIGS.  7  and  9    may be incorporated within any additional or alternate application to detect whether an object is currently visible to a user, regardless of whether that user is scrolling towards the object. 
     For example, and in reference to  FIG.  4   , the exemplary processes of  FIGS.  7  and  9    can be used to detect whether an object is viewable to a user before refreshing content associated with that object, e.g., a refreshable advertisement on a web page. In such an exemplary implementation, the refreshment of content associated with the object, or the execution of a script associated with the object, may replace the polling in step  412  of  FIG.  4   , or may be implemented in addition to the polling of step  412 . 
     In embodiments described above, a user views a portion of a stored web document, e.g., web document  300 , through a viewport, e.g., viewport  390 , by scrolling through the web document to adjust a position of the viewport. In  FIGS.  3 A- 3 C , the web document is disposed according to a “portrait orientation,” i.e., height  360  of web document  300  is larger than a corresponding width of document  300 . As such, the user scrolls through web document  300  along direction  370  of web document  300 , which is parallel with the height of web document  300 . 
     The embodiments described herein are not limited to the exemplary scrolling directions and exemplary orientations of web document  300 . In an additional embodiment, web document  300  of  FIGS.  3 A- 3 C  may be rotated ninety degrees and disposed in a landscape orientation, as depicted in  FIG.  10   . In  FIG.  10   , web document  300  includes text objects  302 ,  304 , and  306 , and media objects  308 ,  310 ,  312 ,  314 , and  316 , as described above in reference to  FIGS.  3 A- 3 C . However, in contrast to the embodiments described above, browser viewport  390  now traverses a body length  1080  of web document  300  in a scrolling direction  1070 . 
     Furthermore, parameters such as an object height, an object offset, and a scroll position may be computed in a similar fashion to that described above in reference to  FIGS.  7  and  9   . In such embodiments, the computed values may be measured in pixels relative not to upper edge  300 A of  FIGS.  3 A- 3 C , but relative to edge  1000 A of  FIG.  10   . In an embodiment, such calculations may be relevant to useful within embodiments that leverage the capability of certain user devices, including, but not limited to mobile devices, to allow the user to view content both in a landscape orientation and in a portrait orientation. 
     The embodiments of  FIGS.  7  and  9    deem an object visible to the user if that object falls, partially or entirely, within the upper and lower edges of the user&#39;s browser viewport, which may be extended to account for the threshold distance. For example, and in reference to  FIG.  3 C , the exemplary processes of  FIGS.  7  and  9    may detect when object  316  becomes visible to the user through viewport  390  as the user scrolls towards object  316 . However, the exemplary processes described above are not limited to the detection and manipulation of objects encountered while the user scrolls through web document  300  vertically along scroll direction  370 . 
     In an additional or alternate embodiment, the exemplary processes described above can also detect and manipulate objects encountered as the user scrolls upwards through web document  300  along scroll direction  370 , i.e., towards upper edge  300 A of web document  300 . For example, as the user scrolls upwards through web document  300  of  FIG.  3 C , the exemplary processes of  FIGS.  7  and  9    can detect when object  307  becomes visible through viewport  390 , and upon detection of object  307 , the exemplary processes of  FIGS.  4 - 6    can perform a corresponding manipulation of object  307 , as described above. 
     Further, for example, the user may scroll through web document  300  in its entirety, thereby positioning lower edge  390 B of viewport  390  at or near lower edge  300 B of web document  300 . In such an embodiment, the user may act to refresh web document  300 , for example, by selecting a “Refresh” icon associated with the user&#39;s web browser, and the exemplary processes described above may be employed to detect objects as the user advances upwards through web document  300 , and to subsequently perform a manipulation associated with the detected objects. 
     Further, in an additional or an independent embodiment, the exemplary processes of  FIGS.  7  and  9    can detect whether an object falls within the horizontal boundaries of the viewport as the user scrolls through web document  300  in a horizontal direction, as depicted in  FIG.  11   . In  FIG.  11   , web document  300  includes text objects  302 ,  304 , and  306 , and media objects  307 ,  308 ,  310 ,  312 ,  314 , and  316 , as described above in reference to  FIGS.  3 A- 3 C . However, in contrast to the embodiments described above, viewport  390  not only traverses body length  380  of web document  300  in a vertical scrolling direction  1170 , but viewport  390  also traverses body width  1182  of web document  300  in a horizontal scrolling direction  1172 . In further contrast to the embodiments described above, body height  380  is larger than a height  394  of viewport  390 , and body width  1182  is larger than a corresponding width  1198  of viewport  390 . 
     In  FIG.  11   , body height  380  of web document  300 , scroll position  392 , and height  394  of viewport  390  may be computed as described above, for example, through the use of one or more JavaScript properties. Furthermore, although not depicted in  FIG.  11   , each object within web document  300  is associated with a corresponding vertical object offset, e.g., offset  340  of object  310  in  FIG.  3 B , and a corresponding object height, e.g., height  330  of object  310  in  FIG.  3 B , which are both measured relative to upper edge  300 A of web document  300  along vertical scrolling direction  1170 . 
     Moreover, in  FIG.  11   , each object within web document  300  is associated with a corresponding horizontal offset and a corresponding object width, each measured relative to a horizontal edge  300 C of web document  300 . For example, object  316  is associated with an offset  1166  and an object width  1156  that, in an embodiment, may be computed by applying one or more appropriate JavaScript functions to a variable associated with object  316 . Further, and similar to the computation of the object offset described above in  FIG.  8   , object offset  1166  may be determined from a previously-computed and stored value of the offset unless width  1182  changes, e.g., through the inclusion of additional content. Although not depicted in  FIG.  11   , each of objects  302 ,  304 ,  306 ,  307 ,  308 ,  310 ,  312 , and  314  is also associated with an offset and a width that, in an embodiment, may be computed in a fashion similar to offset  1166  and width  1156  described above. 
     Moreover, viewport  390  is also associated with a corresponding width  1198  and a corresponding offset  1196 , which may determine a horizontal scroll position. In an embodiment, these parameters may be measured relative to horizontal edge  300 C of web document  300  along horizontal scroll direction  1172 . Further, horizontal scroll position  1196  and width  1198  may be determined through an application of one or more JavaScript properties to a variable associated with viewport  390 , as described above. 
     In an embodiment, the exemplary processes described above can be applied to web document  300  of  FIG.  11    to detect those objects within document  300  that become visible to a user in response to scrolling along vertical scroll direction  1170 , scrolling along horizontal scroll direction  1172 , or a combination of horizontal and vertical scrolling. In such an embodiment, method  900  of  FIG.  9    may deem an object visible to the user when the object falls entirely within horizontal edges  390 C and  390 D of viewport  390  or alternatively, may deem the object visible when the object falls entirely within horizontal edges  390 C and  390 D and vertical edges  390 A and  390 B of viewport  390 . For example, method  900  would deem no objects in  FIG.  11    visible, since none of these objects falls entirely within viewport  390 . 
     However, as described above, the detection process may incorporate a more expansive definition of object visibility. In such an embodiment, method  700  of  FIG.  7    may deem an object within web document  300  visible to the user when at least a portion of the object falls within horizontal edges  390 C and  390 D of viewport  390  or, may alternatively deem the object visible when at least a portion of the object falls within horizontal edges  390 C and  390 D and vertical edges  390 A and  390 B of viewport  390 . For example, exemplary method  700  would deem objects with  302 ,  304 , and  308  of  FIG.  11    visible, since a portion of each of these objects falls within viewport  390 . Once deemed visible to the user, the exemplary methods of  FIGS.  4 - 6    can be applied to perform a manipulation corresponding to the visible object, e.g., downloading content or executing a script. 
     Further, horizontal edges  390 C and  390 D may be expanded along horizontal scroll direction  1172  to account for a horizontal threshold detection distance. In an embodiment, the horizontal threshold detection distance may be identical to that threshold detection distance applied to vertical edges  390 A and  390 B, as described above in reference to  FIGS.  7  and  9   . However, in additional embodiments, the horizontal detection distance may differ from the vertical detection distance, and may be specified as any appropriate non-zero or zero value, without departing from the spirit and scope of the invention. 
     Various embodiments have been described herein with reference to the accompanying drawings. It will, however, be evident that various modifications and changes may be made thereto, and additional embodiments may be implemented, without departing from the broader scope of the invention as set forth in the claims that follow. 
     Further, other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of one or more embodiments of the invention disclosed herein. It is intended, therefore, that this disclosure and the examples herein be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following listing of exemplary claims.