Because URLs can be case sensitive you should type them in exactly as they are given to you. The Web browser, which typically runs on the user's computer system, controls the look and feel of the Web pages to be displayed. Popular Web browsers include Netscape Navigator and Microsoft's Internet Explorer. Although each Web browser behaves a little differently, all are capable of performing certain standard operations such as going back and forward a page, returning you to the home page, reloading a page, creating bookmarks, and so on. As you browse the World Wide Web, you will find information in various forms.
Some pages provide text only.
Others may provide images, video clips, or sound clips. Some text files may be in other formats such as postscript. These programs can take the form of either helper applications or plugins. Helper applications are software programs which are launched when a selected hyperlink points to a data resource that your Web browser cannot handle internally. Plugins are software programs that extend the capability of your web browser by allowing you to run the application from within the browser itself.