|Use this tag if you want to use an|
SGML/HTML validator. Otherwise, this tag is of little use.
<!DOCTYPE ...> declaration (technically it's not a "tag") should be the very first thing in your document... if you choose to use it at all.
<!DOCTYPE ...> tells the browser what version of HTML you are writing in. More specifically,
<!DOCTYPE ...> declares that this document conforms to a specific version of HTML, and specifies what version that is.
The necessity of
<!DOCTYPE ...> is a subject of much debate. The standards published by W3C require the use of
<!DOCTYPE ...>. However, much of the HTML being written does not conform strictly the W3C specifications, and so using
<!DOCTYPE ...> (which is, after all, a claim that you conform to the standards) would seem unnecessary.
<!DOCTYPE ...> has its place on a page, even if you decide to use a little non-standard markup.
<!DOCTYPE ...>'s most useful purpose
is when used in conjunction with one of the various HTML analyzers. The analyzers look to the
<!DOCTYPE ...> to determine what type of HTML you are trying to write. Our recommendation is that you use the appropriate
<!DOCTYPE ...>. It won't hurt and allows you to make use of the HTML checkers available.
This is the
<!DOCTYPE ...> declaration for HTML version 3.2:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
For HTML 4.0, the situation is a little more complicated. There are three standard doctypes. The DTD for documents that strictly conform (don't use any deprecated markup) and that aren't frameset documents, use this
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN"
For a not quite so strict conformance (uses some of the deprecated markup such as
<CENTER ...>), use this
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
Finally, for documents which are frameset documents (the "top" document in a framed page), use this
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Frameset//EN"