Microsoft Meatheads, Netscape Nerds and Lynx Loonies
How To Tell Your Extensions Apart
Developers of software which deals with HTML, particularly Microsoft and Netscape, are notorious for adding their own special little peculiarities to the HTML standard. These added peculiarities are known as Extensions, and there are a lot of 'em. Generally, when they do this, they do it without consulting with each other first to make sure that the "other browser" will support these special little peculiarities. In fact, frequently they introduce these special little peculiarities because of the fact that they know that the "other browser" won't support 'em. Representative examples of these little peculiarities include Microsoft's <BGSOUND> tag, which adds a background sound to a web page. The HTML standard allows authors to add a sound to a web page, which plays when the page loads and works perfectly well on both Netscape's and Microsoft's browser, but Microsoft decided to do it a different way, and the way it ended up, an author who doesn't know that the standard method works on both browsers either adds the sound using both the standard method and the Microsoft method (which doesn't always work), or chooses one or the other and hopes that the user of the "other browser" doesn't notice. Another representative Microsoft extension is the <MARQUEE> tag, which moves if you're looking at it with Microsoft's browser, but is plain, static text if you're using Netscape. On the other side of the fence, Netscape introduced the notorious tag, which annoys the hell out of most Netscape users (and, unfortunately, is used with great abandon by newbie HTML authors who think it's "kewl"), but renders as plain, static text in Microsoft's browser. It's a war... it is known in the computer industry as "The Browser War" and, in general, I try not to participate as much as possible.
Using proprietary extensions to HTML guarantees that if the person who views your finished page isn't using the "correct" browser, they won't be able to see the page exactly the way you designed it. For some people this isn't a problem, but my personal preference is to create pages which do not depend on whose browser you're using to be able to see them correctly.
My general advice is this: Don't use proprietary extensions. If you choose to use them you will also be choosing, to varying degrees, to support the manufacturer of a particular brand of software, and you will be choosing, to varying degrees, to block out people who choose to use software which doesn't support the proprietary extensions you're using. For further information on how to make your HTML pages more non-browser specific please visit the Campaign for a Non-Browser Specific WWW and make your pages "Best Viewed With ANY Browser."</RANT>