h as sums or averages) or other processing on data retrieved from the server 4.Conditionalizing HTML 5.Performing other functions that do not require information from the server Use server processing (the SERVER tag) for these tasks: 1.Maintaining information through a series of client accesses 2.Maintaining data shared among several clients or applications 3.Accessing a database or files on the server 4.Calling external libraries on the server 5.Dynamically customizing Java applets; for example, visualizing data using a Java applet.Lets say a Web Site added convenient navigation to all of its pages. Some of those links sit within pull-down menus to save space on the left hand side of the screen. The menus are typical JavaScript menus, but they present two common problems: First, JavaScript does not work if the browser cannot support it. Second, JavaScript does not work if the client has the JavaScript option toggled off. Server-side help is needed for the pull-down menu to ensure that users can get to a chosen destination. When JavaScript is toggled off and a menu item is selected, the servlet sends the client to the requested page. Java Servlet technology handles this functionality. Servlets enable client/server communication, and because they're written in the Java programming language, they can use the power Java APIs (Application Programming Interface). As server-side applications written in the Java programming language, servlets can create interactive web pages, process forms, search web sites, manage sessions, cookies, and logins, and provide back up for other technologies such as JavaScript. A form is a powerful web site tool, enabling clients to take polls, enter personal information for online shopping, or subscribe to an e-newsletter. In other words, forms turn static web pages into dynamic pages. But a form cannot give instructions to a server. Without an application between the form and the server, the form is useless. S...
