Adobe 38028779 Getting Started Guide - Page 221

In the case of web applications, certain lines of code are undetermined when the visitor requests the page. These lines must be determined by some mechanism before the page can be sent to the browser. The mechanism is discussed in the following section. Processing dynamic pages When a web server receives a request for a static web page, the server sends the page directly to the requesting browser. When the web server receives a request for a dynamic page, however, it reacts differently: It passes the page to a special piece of software responsible for finishing the page. This special software is called an application server. The application server reads the code on the page, finishes the page according to the instructions in the code, and then removes the code from the page. The result is a static page that the application server passes back to the web server, which then sends the page to the requesting browser. All the browser gets when the page arrives is pure HTML. Here's a view of the process: Step 1 - Web browser requests dynamic page. Step 2 Web server finds page and passes it to application server Step 3Application server scans page for instructions and finishes page. Web browser Request Response WEB SERVER Hi Application server Step 5 - Web server sends finished page to requesting browser Step 4Application server passes finished page back to web server How a web application works 221