Here’s the 3 DTD used in XHTML. I have included them here for easy access for cut–and–paste when you’re creating your new XHTML compliant web document. Remember‚ if you plan on having a web page that passes the W3C validation test’s you MUST declair a doctype at the very beginning of your file.
If your new to XHTML and used to programming in HTML‚ then use the XHTML Transitional doctype. This will render the file slightly different. It’s a little more lenient as to the html/xhtml transition process.
XHTML 1.0 Strict
XHTML 1.0 Transitional
XHTML 1.0 Frameset