In the early days of the web, most websites were just repositories of static information. As the web has grown in capacity, however, it has also grown in capability. Today organizations want to do more with their websites, such as provide customized information for users and allow people to conduct commercial transactions. These capabilities require dynamic web pages.
Simple web applications deliver static pages. As the term implies, content on static pages does not change. A developer creates a static page and puts it on a server where a user can request it. The components of a static page, such as text, images, and other embedded objects, are present in the code of the page, and change only when a developer manually modifies the page. Static pages are processed as follows (see Figure 1):
Figure 1. Process for static web pages
In many cases, a web page must be able to deliver content that changes, either over time or by a user. For example, the following scenarios require dynamic processing:
Dynamic page processing is similar to static page processing, but includes some additional steps (see Figure 2):

Figure 2. Dynamic web page process