What Are Web Standards?
First off, what are web standards? What makes the standard? And for that matter, why should you even care?
Web standards are designed to make the web easier to use and more powerful for both users and webmasters. They are established by a non-profit organization known as the World Wide Web Consortium (W3C) and by other standards groups.
Pages that are written according to web standards are smaller and take less time to download than old-fashioned pages that are not. This is especially important to users with slower connections… No one wants to sit around and wait for pages to load all day.
Since web standards specify exactly how your code should be displayed by browsers, you don't have to worry about your site working in one browser but not in another. Your site will work equally well in any standards-compliant browser.
The most important reason to use web standards is that they allow you to separate structure, presentation, and behavior from each other. Structure is specified by XHTML, presentation by CSS, and behavior by DOM-based scripting. This means that if you want all your pages to look the same, you can just tell them all to use the same style sheet file. If you want to change how they all look, just change that one style sheet file and all your pages will look different.
Web standards consist of XHTML, the actual structural markup which describes the content of your page; CSS, which specifies how your page should look; and finally ECMAScript (the standard version of JavaScript) and the DOM, which together let you add advanced interactive behaviors to your site. ECMAScript and the DOM are outside the scope of this tutorial.
Not all browsers support web standards equally well, but the vast majority of browsers in use today support them well enough. Version 4.0 browsers (dating from the height of the Netscape–Internet Explorer browser wars) were notorious for their lack of standards support. Current versions of Internet Explorer, Netscape, Firefox, Safari, and Mozilla all support web standards quite well, though no browser has perfect support.
The Web Standards Project is a group devoted to promoting web standards, and they do a much better and more through job of explaining what web standards are and why they matter.
