Browser Specific Markup
Everyone has seen the logo, or read the advisement, "This page enhanced for..." followed by the name of one of the "Big Two" browsers. This is called Netscapism and Microsoftism. Web developers feel that they need to create their page to look good on one browser. They add the logo, add the text, or even have JavaScript alert boxes to let you know if you are using "the right browser".
"So what?" you say. "Everyone has to make their page look good on one browser or another!" But why? Why do you have to do it? The answer, you don't. The World Wide Web was designed to be global, and universal. This means all browsers.
The World Wide Web Consortium (W3C) sets the standards for html; the reason for one main body is to promote world wide access, and prevent different versions, separation, and the eventual demise of the Web. The browser makers, in an attempt to promote their own browser, have adding their own tags (i.e. <blink> for Netscape, and <marquee> by Microsoft). These tags should not be used on the Web, and developers should be more concerned with valid markup.
"How do I know if I'm using browser specific tags, or if my markup is valid?" That's when you use a "validator". You can find links to validation services in the Validate Your HTML lesson.
WAI Accessibility Guidelines: Page Authoring
"Anyone who slaps a 'this page is best viewed with Browser X' label on a Web page appears to be yearning for the bad old days, before the Web, when you had very little chance of reading a document written on another computer, another word processor, or another network."
-Tim Berners-Lee in Technology Review, July 1996
