Learning PHP & MySQL, 2nd Edition

Chapter 1. Dynamic Content and the Web

To the average user, a web page is a web page. It opens in the browser and provides information. Looking closer, though, some pages stay mostly the same, while other pages change regularly. Pages that don’t change—static pages—are relatively simple to create. Someone has to create an HTML document, by hand or with tools, and upload it to a site where web browsers can visit. One of the most common tools to create HTML documents is Adobe Dreamweaver. When changes are needed, you just replace the old file with a new one. Dynamic pages are also built with HTML, but instead of a simple build-and-post approach, the pages are updated regularly, sometimes every time that they are requested.

Static sites provide hyperlinked text and perhaps a login screen, but beyond that, they don’t offer much interaction. By contrast, Amazon.com (http://www.amazon.com) demonstrates much of what a dynamic web site can do: your ordering data is logged, and Amazon offers recommendations based on your purchasing history when you access their page. In other words, dynamic means that the user interacts with the web site beyond just reading pages, and the web site responds accordingly. Every page is a personalized experience.

Creating dynamic web pages—even a few years ago—meant writing a lot of code in the C or Perl languages, and then calling and executing those programs through a process called a Common Gateway Interface (CGI). Having to create executable files wasn’t much ...