Doctypes That Work
An interesting tidbit... At a conference I asked Molly if the DTD had to be referenced from the W3.com server and she said yes. I haven't verified this independantly yet though. My thought was to add the DTD to the local server and reference it there to prevent reliance on a server I have no control over. Perhaps that might defeat browser caching or something?
You can create a Custom DTD if you want to change validation rules - like adding deprecated elements so errors are not thrown.
HTML 4.01 Strict, Transitional, Frameset
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN"
"http://www.w3.org/TR/html4/frameset.dtd">
XHTML 1.0 Strict, Transitional, Frameset
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">
For XHTML documents, add the following to the HTML element
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
XHTML 1.1 DTD
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
Content Type
Don't forget to define the Content Type. If you are going to use inline style elements, define the Content-Style-Type.
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <meta http-equiv="Content-Style-Type" content="text/css" />