XHTML Compliant and Verified

Web pages that are viewable in a browser are typically coded in HTML (the markup language of the web). Over the years, web pages have continued to degrade because of the need to mix layout with formatting. In addition, browser developers have added tags that their browser will render but other browsers will not, resulting in pages that can not be portable. HTML, then, at least the early versions, has evolved into a problematic issue for web site developers.

The specifications for HTML are developed, revised and maintained by the W3C organization.

XHTML ( EXtensible Hyper Text Markup Language ), then, has been developed to alleviate some of the problems inherent with HTML, and is a more strict and cleaner specification for coding web pages. XHTML will gradually replace HTML so it is important to acknowledge and use the latest version as recommended by the W3C. Browser developers as well have included XHTML support in the latest versions of their products.

What was wrong with pages coded in HTML? Most importantly, pages with "bad" coding would display properly in browsers due to the forgiving nature of their parsers. In fact, nearly anything would display properly, which has led many down the wrong path creating pages that are not properly formed. XHTML, on the other hand, can be validated for correctness, leading web page developers in the direction of creating "correct" code for web pages they build. Since today's markets also include hand held devices and other technologies, only validated and correct markup can be displayed as this new technology simply doesn't have the resources available to properly handle incorrect markup.

Here are a few new rules that must be followed when developing XHTML compliant code:

• tags must be lowercase
• attributes must be lowercase
• attributes must be quoted
• tags must be properly nested
• attribute minimization is not allowed
• the "id" attribute replaces the "name" attribute
• all pages must have a doctype defined at the top of the page
• empty tags are not allowed

XHTML contains everything a web developer would need to produce valid code. All new pages and new development projects should be striving to create valid XHTML marked up pages. You can test the "correctness" of pages by visiting http://validator.w3.org and entering the URL of the page you wish to check.