Datasheet

Figure 1-1
This is where CSS enters the picture. If CSS is present in the document, the CSS describes what the
HTML page should look like to the browser. If the browser understands the CSS, it processes the web
page into something you can see and interact with. If the browser understands only some of the CSS, it
generally ignores what it doesn’t understand. If the browser doesn’t understand CSS at all, it usually
displays a plain-looking version of the HTML document.
How CSS Came to Be
During the mid-1990s, use of the Internet exploded. At that time, HTML was the only option for present-
ing a web page. As the Internet began to be used by more regular folks (as opposed to government, edu-
cational institutions, and researchers, as in the early days), users began demanding more control over
the presentation of HTML documents. A great quandary arose — clearly HTML alone was not good
enough to make a document presentable. In fact, not only was it not good enough, HTML alone simply
wasn’t suited for the job. HTML did not have the functionality that professional publishing required and
had no way of making magazine- or newspaper-like presentations of an electronic document.
5. HTTP server sends the web document.
Server-side
Client-side
6. Your browser receives the document.
7. Your browser processes the source code.
8. The browser displays the web page.
4. HTTP server looks up the web document.
3. HTTP server receives the request from the browser.
2. Browser contacts the HTTP server at that address.
1. You type a www address into the browser.
6
Part I: The Basics
05_096970 ch01.qxp 4/20/07 11:27 PM Page 6