Abstract:
A system and method are disclosed for modifying a document format. In one embodiment, a structure of a first document is extracted to form a first data structure. The first data structure is then modified to form a second data structure. Content from a second document is extracted from the second document and inserted into the second data structure to permit display of the content of the second document in the format of the second data structure.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit and priority of U.S. Provisional Patent Application No. 60/269,498 entitled “Navigation Control Module” filed Feb. 16, 2001 and of U.S. Provisional Patent Application No. 60/284,354 entitled “Enhanced Navigation Control Module (ENCM)” filed Apr. 16, 2001, the disclosures of which are hereby incorporated by reference in their respective entireties. 
     
    
     
       CROSS REFERENCE TO ATTACHED COMPACT DISK APPENDIX  
         [0002]    A Compact Disk Appendix, of which two identical copies are attached hereto forms a part of the present disclosure and is incorporated herein by reference in its entirety. The Compact Disk Appendix contains the following files: Automa˜1.cpp, 41 KB, 02/13/2002; Automa˜1.h, 2 KB, 02/13/2002; Classify.cpp, 15 KB, 02/13/2002; Classify.h, 1 KB, 02/13/2002; Handle˜1.cpp, 25 KB, 02/13/2002; Handle˜1.h, 4 KB, 02/13/2002; Ncmmgr.cpp, 8 KB, 02/13/2002; Ncmmgr.h, 1 KB, 02/13/2002; Url.cpp, 2 KB, 02/13/2002; and Url.h, 1 KB, 02/13/2002.  
         RESERVATION OF COPYRIGHT  
         [0003]    A claim of copyright protection is made on portions of the description in this patent document, including the contents of the Compact Disk Appendix. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, exactly as it appears in the Patent and Trademark Office patent file or records, but reserves all other rights whatsoever.  
         TECHNICAL FIELD  
         [0004]    The present invention relates to a system and method for modifying a document format.  
         BACKGROUND  
         [0005]    Handheld devices, including Personal Digital Assistants (PDAs) and cellular telephones, offer connectivity to the Internet and permit access to documents available over the Internet. Wireless Application Protocol (WAP) is a standard for providing cellular phones, PDAs, pagers and other handheld devices with secure access to web pages. WAP features the Wireless Markup Language (WML), which generally serves as a universal medium for translating web-based HTML content into a format that accommodates small form factor displays and key sets found on conventional handheld devices. WML also allows handheld device manufacturers to include microbrowsers in their products that accept WML input from a WAP-based system across vast regions of the world.  
           [0006]    A packet-based service called “i-Mode” provides information service for mobile telephones and permits users of mobile telephones to browse web content via a mobile telephone. In recent years, the number of users of the i-Mode standard has increased dramatically, perhaps most significantly in the United States and Japan.  
           [0007]    The proliferation of wireless PDAs has also created a popular means for handheld Internet access. However, presenting IP-based content, and other content developed for display on large form factor devices (e.g., PC monitors), on small form factor screens of handheld devices has, in the past, been problematic. Two primary methods of presenting such content to handheld devices have been employed.  
           [0008]    The first such method can be termed “fixed mapping.” Fixed mapping typically involves rewriting an existing document, such as an HTML-based web page, to conform to a specific standard, such as WAP or i-Mode. A web server must then maintain the rewritten web site as a separate site with its own URL in addition to the original document. As new content is added to the original document, a web site operator must manually trim, edit, and condense the new content by rewriting the new content into a format that will accommodate the interface parameters of handheld devices. This method is limited in that considerable time and expense are typically required to maintain the two web sites in parallel. Further, the manual editing of the rewritten web site can be time-consuming, burdensome, and expensive.  
           [0009]    The second method may be termed “transcoding.” Transcoding typically involves the use of software that takes the entire content of a web site as input, converts the entire content into a format of a specific handheld wireless standard for transmission to handheld devices. The entire content, as formatted according to a handheld wireless standard, is then transmitted to the handheld device. This conversion may be performed “on-the-fly” (i.e., automatically in real time) or may be performed manually.  
           [0010]    Transcoding has the advantage of reducing the investment to reach wireless markets since it leverages existing web sites. From a user standpoint, transcoding is desirable in that it preserves all the text-based information from the originating site. For large volumes of text, however, using this approach may overwhelm the handheld device user with large volumes of text to be viewed on a small form factor display. Further, the unorganized transcoded content makes changes or modifications to the wirelessly enabled web site more difficult for the web site operator.  
           [0011]    In addition, many wireless handheld devices have limited bandwidth. For example, today, many wireless handheld devices have data rates in the range of about 9.6-64 kbs. Thus, downloading an entire web page designed for viewing on a large form factor device at data rates common to handheld wireless devices may require large download times. These large download times may be burdensome to the user who must wait while the entire web page downloads, even though the user may only desire to view a portion of the web page. Further, these large download times may be expensive for users who pay for wireless service based on the amount of time or the number of packets downloaded. For example, some i-Mode services charges are packet-based so downloading large pages cost more to download than smaller pages if the larger pages result in more data packets being sent to the user.  
           [0012]    Additional background details are disclosed in U.S. Pat. No. 6,336,124, the disclosure of which is hereby incorporated by reference.  
         SUMMARY  
         [0013]    Accordingly, a need exists to provide a system and method for presenting content developed for display on large form factor devices (e.g., PC monitors) on small form factor screens of handheld devices.  
           [0014]    Pursuant to one embodiment of the present invention, a document having a first structure is divided into multiple blocks, or sub-documents. Content of the blocks is arranged in a list such that individual entries of the list include the content of associated blocks. A database is provided that includes a data structure associated with the document. The data structure stored in the database specifies a manner of displaying the list entries. Then, the entries of the list arc inserted into the data structure to form an output file formatted in accordance with the data structure. Portions of the output file may then be transmitted over a network, such as the Internet, to a client device. The client device may comprise a PDA, a mobile telephone, a pager, or the like. Thus, according to this embodiment, regardless of the specific contents of the document, which may change from time to time, the document is reformatted pursuant to the associated data structure stored in the database.  
           [0015]    According to another aspect, the database entry associated with a document may include labels associated with one or more of the entries of the list. The database entry associated with the document may also specify that certain of the entries of the list not be displayed at all at the client device. Further, the database entry associated with the document may specify an order in which various entries of the list are displayed at the handheld device.  
           [0016]    In one embodiment, the database comprises an element of an application server and may be configured remotely over a network, such as the Internet or an intranet. For example, a user at a client personal computer may access the application server over the network using a web browser. Specifically, the user may specify, for a particular document, such as a web page, the manner in which the document will be displayed at a client handheld device by adding, or modifying, an entry in the database associated with the document.  
           [0017]    The contents of the database may be configured, or modified, by different means. For example, if the application server were hosted on a personal network, the owner, or system administrator, of the personal network could configure the contents of the database from any client computer coupled to the personal network, such as via the Internet or an intranet. Alternatively, if the application server were hosted by a corporation, the contents of the database may be configured by the owner, or system administrator for the document for which the database is being modified.  
           [0018]    In this regard, pursuant to an example embodiment of the present invention, the application server provides the user at the client personal computer with visual representation of the document with identifiable tags or labels. These visual tags or labels are provided to facilitate user modification of the underlying tree data structure of the document as formatted for a large form factor display. The user then modifies the tree data structure by, for example, deleting entries, moving entries, and changing labels assigned to various nodes of the data structure to form a modified data structure. This modified data structure is then later used by the application server to reformat the associated document for display at a small form factor display of a client.  
           [0019]    Pursuant to another aspect of the present invention, the application server generates an output file associated with the document that includes a table of contents (TOC) and a set of sub-documents associated with the document. The table of contents comprises a page including the labels assigned to the various blocks of the document and the sub-documents comprise the content of associated blocks. Accordingly, in operation, when a small form factor client device requests a document from the application server, the application server returns the table of contents page, rather than all of the content of the entire document itself. The table of contents page includes links associated with entries in the table of contents page. These links comprise the addresses of associated sub-documents to permit the user to request a sub-document by selecting the associated, or corresponding, link.  
           [0020]    Additional details regarding the present system and method may be understood by reference to the following detailed description when read in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]    [0021]FIG. 1 is a block diagram of a document delivery system in accordance with one embodiment of the present invention.  
         [0022]    [0022]FIG. 2 is a block diagram of the formatter of FIG. 1  in accordance with one embodiment of the present invention.  
         [0023]    [0023]FIG. 3 is a block diagram of the mapper of FIG. 2 in accordance with one embodiment of the present invention.  
         [0024]    [0024]FIG. 4 illustrates a tree data structure in accordance with one embodiment of the present invention.  
         [0025]    [0025]FIG. 5 is a block diagram of the control module of FIG. 2 in accordance with one embodiment of the present invention.  
         [0026]    [0026]FIG. 6 is a flowchart illustrating a method in accordance with one embodiment of the present invention.  
         [0027]    Common reference numerals are used throughout the drawings and detailed description to indicate like elements. 
     
    
     DETAILED DESCRIPTION  
       [0028]    FIG. 1  illustrates a document delivery system  100  in accordance with one embodiment of the present invention. The document delivery system  100  permits a client  102  to access content of documents (not shown) stored at server  104 , server  106 , or other servers  108  over a network  110 , such as the Internet, and over a network  111 , such as an intranet.  
         [0029]    In one embodiment, the client  102  comprises a handheld device, such a PDA (Personal Digital Assistant), a mobile telephone, or the like, having a small form factor display  112 . The client  102  also includes a web browser  114 . The web browser  114  may comprise a microbrowser designed for small display screens on web-enabled cellular telephones, PDAs and other handheld devices, including wireless handheld devices.  
         [0030]    The client  102  may exchange data with the network  110  in a wireless fashion via a wireless station  120  and a gateway  122  in accordance with WAP (Wireless Application Protocol), i-Mode, or other suitable protocol or service. Optionally, the client  102  may exchange data with the network  110  via a wired connection (not shown).  
         [0031]    The client  102  may also exchange data with the network  111  in a wireless fashion via a wireless station  121  and a gateway  123  in accordance with WAP (Wireless Application Protocol), i-Mode, or other suitable protocol or service. Optionally, the client  102  may exchange data with the network  111  via a wired connection (not shown).  
         [0032]    In one embodiment, the gateways  122 ,  123  are network devices that connect a wireless network with a wired network, such as the networks  110 ,  111 . Access between the client  102  and application server  124  may also pass through one or more other firewalls (not shown), other gateway devices (not shown), or the like.  
         [0033]    Pursuant to one embodiment, the client  102  transmits requests for documents stored on one or more of the servers  104 ,  106 ,  108  to the application server  124 . The request for content may comprise an HTTP request or other suitable type of request. Moreover, the application server  124  may alternatively receive the request for a document from the client  102  from any network (e.g.,  110 ,  111 ). The application server  124 , among other functionality, functions as a proxy server and receives requests for documents from client devices, such as the client  102 , over the networks  110 ,  111  and provides associated content in response to such requests by transmitting the associated content over at least one of the networks  110 ,  111 .  
         [0034]    In response to a request for a document from the client  102 , the application server  124  requests the document identified by the request from one or more of the servers  104 ,  106 ,  108 . Upon receipt of the document identified by the request, the application server  124  modifies the format of the document identified by the request for content using a formatter  126 .  
         [0035]    In one embodiment, the document identified by the request is an HTML or XML web page, although other document types, such as PDF (Portable Document Format), may also be requested. The application server  124  then transmits at least a portion of the reformatted content of the document identified by the request to the client  102  in a format compatible with the browser  114  for display at the display  112  of the client  102 .  
         [0036]    The formatter  126  includes a database (see, FIG. 5) that may be configured from a client admin computer  140  via a database modifier  128 . The database modifier  128  may comprise a JavaScript module that penn its a user at the client admin computer to visually modify a data structure of a document into a desired format. The modification may be performed by, for example, adding labels, re-ordering, moving, deleting, or otherwise changing portions of the data structure and stores the changed, or modified version of the data structure in the database.  
         [0037]    In particular, the client admin computer  140  includes a web browser  142 , Such as Internet Explorer™ by Microsoft Corporation or other suitable web browser for permitting a user at the client admin computer  140  to view pages at a the database modifier  128  hosted at the application server  124 . The pages at the database modifier  128  of the application server  124  permit user configuration of the FIG. 5 database, as discussed in more detail below.  
         [0038]    In general, the formatter  126  receives the document identified by the request from one of the servers  104 ,  106 ,  108 , divides the document into multiple blocks, and assigns labels to individual blocks. The formatter  126  then generates a list containing the content of the various blocks. The formatter  126  then uses a data structure associated with the document and stored at the application server  124  to generate an output file using the generated list of content. The output file may contain a Table of Contents (TOC) page and sub-documents. The TOC page lists labels associated with the sub-documents and may contain links to the sub-documents. The formatter  126  then transmits the TOC page, a headline, an image, or other content specified by a database at the application server  124  to the client  102  over at least one of the networks  110 ,  111 . Details of the operation of the formatter  126  are discussed in more detail below.  
         [0039]    [0039]FIG. 2 illustrates details of the formatter  126  of FIG. 1  according to one embodiment of the invention. As shown, the formatter  126  includes a mapper  202 , and a control module  206 , which may comprise software written in C++ or other suitable programming language. The mapper  202  receives the requested document and reformats the document as a list of document content  204 . The control module  206  then generates an output file using the list document content  204 . Additional details regarding the mapper  202 , the list of document content  204 , and the control module  206  are discussed below.  
         [0040]    [0040]FIG. 3 illustrates details of the mapper  202  of FIG. 2 according to one embodiment of the invention. The mapper  202  includes a number of software modules stored in a computer readable medium. In particular, the mapper  202  includes a network interface  302 , a parser  304 , a label engine  306 , a data structure converter  308 , and a ranking engine  310 . The network interface  302  receives the document requested from the network. As mentioned above, the document requested may comprise a web page, such as an HTML document, and XML document, or the like.  
         [0041]    The parser  304  parses and decomposes the document into a tree data structure. FIG. 4 illustrates an example tree data structure  400 , which may comprise a structural representation of a document, such as an HTML web page. As shown, the tree data structure  400  includes a root node  402  associated with the document. The parser  304  (FIG. 3) divides the document into multiple blocks and represents each block of the document as a table node  404  in the tree data structure  400 . Each table node  404  has at least one row node  406  as a child node. Individual row nodes  406  each have at least one column node  408  as a child node. The column nodes  408  may then have additional table nodes as children. At this point, the tree data structure  400  may be recursive.  
         [0042]    Thus, the document is divided into blocks, which may be defined by the structure of the document. The primary content for each of the blocks, or tables, is stored in the column nodes  408  and the remaining structure of the various blocks is represented in the other portions of the tree data structure  400 .  
         [0043]    Referring again to FIG. 3, the label engine  306  then assigns labels to individual blocks and may assign a classification to each block according to the contents of the block. In one embodiment, the label engine  306  assigns a classification to each block based on the block contents. For example, if the document is a web page, the web page may include links, text, forms, and pictures, as well as other classes of content.  
         [0044]    The label engine  306  optionally analyzes individual blocks and assigns a classification to the block indicating the type, or class, of content in the block. Hence, a block that contains primarily links may be assigned a “navigation” classification, a block that contains primarily text may be assigned a “story” classification, a block that contains primarily pictures may be assigned an “image” classification, and a block that contains form information like an address may be assigned a “form” classification. The label engine  306  inserts a classifier associated with the assigned classification for each block into the table node of each block.  
         [0045]    After classifying the blocks, the label engine  306  optionally merges, or combines, column nodes of each block that have the same classification. For example, if a given block has multiple column nodes having the classification of “story,” the label engine  306  would merge, or combine, the content of these column nodes. Likewise, if a given block has multiple columns having the classification of “navigation,” the label engine  306  would merge, or combine, the content of these column nodes.  
         [0046]    In one embodiment, the label engine  306  may merge, or combine, column nodes in accordance with predetermined merging rules stored at the label engine  306 . An example merging rule is that a large “story” node is not merged with another large “story” node. Another example merging rule is that a small “story” node may get merged with a “navigation” node. Thus, according to these rules, a large story, which is likely to be substantial enough to be viewed in isolation, will not be combined with another large story. However, a small story would not be isolated as a data packet associated with the small story may be able to contain additional information, such as one or more links. The specifics of these merging rules may vary and may be customized according to particular applications. The classifying and merging are optional according to some embodiments of the invention.  
         [0047]    The label engine  306  also assigns a label to each block according to the block contents. In one embodiment, the label engine  306  uses the first several words of text of a block including text as the label for that block. In another embodiment, the label engine  306  assigns a label to a block based on the classification of the block. The label engine  306  then adds the assigned label to the table node of the associated block.  
         [0048]    With continued reference to FIG. 3, a data structure converter  308  of the mapper  202  next “flattens” the tree data structure by converting the tree data structure into a linear, one-dimensional list containing the content of the column nodes  408 . The table nodes  404  and the row nodes  406  are not included in the one-dimensional list. Individual entries in the one-dimensional list include the content of an associated column nodes  408 .  
         [0049]    A ranking engine  310  then ranks the entries in the one-dimensional list according to the content of the individual entries. In one embodiment, the ranking engine  310  analyzes characteristics of each entry and assigns a “weight” value to each entry. The weight assigned to each entry may be based on a variety of parameters, including, for example, the size of the font used in the entry, whether the text in the entry is boldface, the color of the text, whether the text is flashing, whether the text is underlined, and the position of the item in the document. Based on parameters such as these, the ranking engine  310  assigns a weight to individual entries in the one-dimensional list and then reorders the one-dimensional list according to the weighted rankings.  
         [0050]    In one embodiment, the ranking engine  310  reorders the list in an order of decreasing weight values such that the first entry in the re-ordered list is the entry having the largest weight value and the last entry in the list the entry having the smallest weight value. The re-ordered list is then stored as the list of document content  204  (FIG. 2). Thus, in some embodiments, entries having large or bold text may be ranked before entries having smaller or plain text. Also, entries having a graphic may be ranked higher than entries having primarily links.  
         [0051]    [0051]FIG. 5 illustrates details of the control module  206  of FIG. 2 in accordance with one embodiment of the present invention. In general, the control module  206  receives the list of document content  204  and creates a new document structure according a navigation rules database  502  and the list of document content  204 .  
         [0052]    The navigation rules database  502  contains a tree data structure for one or more documents. In one embodiment, contents of the navigation rules database  502  may be modified by accessing the formatter  126  (FIG. 1) from a client computer, such as the client admin computer  140  (FIG. 1). The database modifier  128  may modify the contents of the navigation rules database  502  described above.  
         [0053]    In particular, the client admin computer  140  includes browser  142  and permits a user to access the database modifier  128  and to modify the contents of the navigation rules database  502 . To modify the contents of the navigation rules database  502 , a user at the client admin computer  140  directs the browser  142  to the database modifier  128 . The database modifier  128  then presents the user with a GUI (Graphical User Interface) via the browser  142  that permits the user to view a default tree data structure, as constructed by the mapper  202 , for a given document, such as an HTML or XML web page document. The default tree structure may be the structure of the document at issue as determined by parsing the document.  
         [0054]    The user may then delete entries in the tree data structure. The user may alternatively move tree data structure entries from one location to another within the tree data structure. Further, the user may change the label or classification assigned to given nodes within the tree data structure. After the user has thus modified, or customized, the tree data structure, the control module  206  stores the modified tree data structure as an entry in the navigation rules database  502  associated with the document.  
         [0055]    The control module  206  also includes a URL (Uniform Resource Locator) checker  504 . The URL checker  504  receives the list of document content  204  from the mapper  302  and determines whether the navigation rules database  502  includes a tree data structure associated with the list of document content  204 . In one embodiment, the URL checker determines whether the URL associated with the list of document content  204  matches a URL associated with an entry in the navigation rules database  502 . If such a match exists, an output file generator  506  retrieves the tree data structure in the navigation rules database  502  associated with the list of document content  204 . The output file generator  506  then creates an output file  508  based on the retrieved tree data structure using the content of list of document content  204 .  
         [0056]    The output file  508 , in one embodiment, includes a table of contents (TOC) page that lists the labels of the document. The output file  508  also contains one or more sub-documents. Individual sub-pages are associated with individual entries in the TOC. One or more of the labels, or entries, of the TOC may include links to associated sub-documents.  
         [0057]    If the URL checker  504  determines that the navigation rules database  502  does not include a tree data structure associated with the list of document content  204 , then the output file generator  506  generates an output file  508  that includes a TOC page that lists the labels of the document. One or more of the labels, or entries, of the TOC may include links to associated sub-documents.  
         [0058]    The formatter  126  then transmits the TOC page over at least one of the networks  110 ,  111  to the client  102 . Upon receipt of the TOC page at the client  102 , the client  102  displays the TOC page at the display  112  of the client  102 . The user may then select a link associated with one of the entries of the TOC, which requests an associated sub-document from the output file  508 . In response to a request for a sub-document in the output file  508 , the formatter transmits the requested sub-document to the client  102  over at least one of the networks  110 ,  111  for display at the display  112  of the client  102 .  
         [0059]    [0059]FIG. 6 illustrates a flowchart  600 , which depicts a method according to one embodiment of the present invention. The method commences at block  602  where application server  124  receives a request for document from the client  102  (FIG. 1), the requested document residing on at least one of the servers  104 ,  106 ,  108 . The request for document may be directed to the application server  124  directly. Alternatively, the request for document may be directed directly to one of the servers  104 ,  106 ,  108 , which, in turn, redirects the request for document to the application server  124 . The request for document may comprise an HTTP request or other suitable request. Moreover, the requested document may comprise a document in HTML, XML, PDF, or other suitable format.  
         [0060]    Next, at block  604 , the application server  124  retrieves the requested document from one or more of the servers  104 ,  106 ,  108  on which the document resides. This retrieval may be accomplished by the application server  124  transmitting an HTTP request to the server  104 ,  106 ,  108  at which the requested document is stored. For example, if the requested document resides at the server  104 , the application server  124  requests the document from the server  104  over the network  110  and receives the requested document over the network  110 .  
         [0061]    Then, at block  606 , the formatter  126  of the application server  124  extracts a structure of the retrieved document. In one embodiment, a parser  304  (FIG. 3) parses the retrieved document and generates a tree data structure representing the structure of the retrieved document. An example of such a tree data structure is illustrated in FIG. 4 and is described above.  
         [0062]    For individual nodes of the tree data structure that include document content, the formatter  126  next analyzes the content of the nodes and assigns one of a set of predefined classifiers to each of the nodes based on the content of the nodes, pursuant to block  608 . As discussed above, for a node having content comprising primarily text, the label engine  306  of the formatter  126  may assign a “story” classifier to the node. The classifier may comprise a text string or other identifier added to the node.  
         [0063]    At block  610 , the label engine  306  of the formatter  126  assigns labels to individual nodes of the tree data structure that include document content. The label engine  306  may assign a label based on the content of the node, the assigned classification of the node, or both. In one embodiment, the label engine  306  uses the first several words of nodes having text content as the label for the associated node. The label may indicate the content of the node being labeled.  
         [0064]    At block  612 , the label engine  306  merges nodes having content according to their classification. For example, if a pair of nodes having content both have the classification “navigation,” then the label engine  306  merges the content of these nodes to form a single node that includes the content of the merged nodes. Block  612  may alternatively be performed before block  610 .  
         [0065]    At block  614 , the data structure converter  308  of the mapper  202  converts the tree data structure to a list. The data structure converter  308  extracts the nodes of the tree data structure that include content and generates a list comprising the nodes of the tree data structure that include content, without the other associated nodes, such as table and row nodes, which do not include content.  
         [0066]    Next, at block  616 , the ranking engine  310  (FIG. 3) of the mapper  202  reorders the entries of the list generated at block  614 . In one embodiment, the ranking engine  310  assigns a weight value to each of the entries in the list according to certain parameters of the content of the entries, the classification of the list entry, or a combination thereof. Then, the ranking engine  310  reorders the list according to the weight value of the list entries. For example, the ranking engine  310  may order the list entries in order of decreasing weight value. The ranking engine  310  then stores the re-ordered list as the list of document content  204  (FIG. 2).  
         [0067]    The control module  206  (FIG. 5) then determines whether the navigation rules database  520  includes an entry associated with the list of document content  204 , pursuant to block  618 . In one embodiment, the URL checker  504  of the control module  206  determines whether a URL associated with the list of document content  204  matches a URL associated with an entry in the navigation rules database  502 . The URL checker  504  determines that the navigation rules database  502  contains an entry associated with the list of document content if such a match exists and execution proceeds to block  620 , else execution proceeds to block  622 .  
         [0068]    At block  620 , the output file generator  506  creates a new data tree structure according using the list of document content  204  and the associated entry of the navigation rules database  502 . The entry of the navigation rules database  502  may specify labels to be assigned to the various nodes, the location of the various nodes within the new data tree structure, and whether certain nodes are included in the new data tree structure. The output file generator  506  then creates a new data tree structure according to the entry in the navigation rules database  502  and inserts the associated content from the list of document content  204  to form a new data tree, which may be stored as the output file  508 .  
         [0069]    At block  622 , the output file generator  506  stores the new data tree structure as the output file  508  if the navigation rules database  502  contains as entry associated with the list of document content  204 . Otherwise, the output file generator  506  stores the list of document content as the output file  508 .  
         [0070]    The output file  508  includes a table of contents (TOC) page that lists the labels of the nodes having content and sub-documents that include the content of blocks associated with the labels. Each of the sub-documents is associated with one of the links so that a user at the client  102  may request a sub-document by selecting the link associated therewith.  
         [0071]    Lastly, pursuant to block  624 , the formatter  126  transmits the TOC page to the client  102 .  
         [0072]    The above-described embodiments of the present invention are meant to be merely illustrative and not limiting. Thus, those skilled in the art will appreciate that various changes and modifications may be made without departing from this invention in its broader aspects. Therefore, the appended claims encompass such changes and modifications as fall within the scope of this invention.