How To Write a Web Application ?
A typical web application starts when a user clicks a link in an HTML page and causes the browser to instigate an HTTP request/response transaction with a web server, CGI program, and web application server. For the purposes of this article, I will refer to the web server, CGI program, and web application server as the targeted server.
The targeted server receives the HTTP request and dispatches the request and its associated data (such as headers and query parameters) to the desired resource residing on the targeted server. In the simplest case, the targeted server responds with a static HTML page, which the browser interprets and presents to the user. In more complex web applications, the targeted server must perform other functions such as the following:
* Execute business logic
* Retrieve data according to query parameters
* Authenticate and authorize users
* Reestablish a session from a former request
* Exchange data with legacy systems
Build the HTML response page dynamically to be passed back to the browser