In the rest of this tutorial we will assume that you are serving pages to be rendered in standards mode by relatively up-to-date user agents.

We recommend the use of XHTML wherever possible; and if you serve XHTML as text/html we assume that you are conforming to the compatibility guidelines in Appendix C of the XHTML 1.0 specification.

We recognize that XHTML served as XML is still not widely supported, and that therefore many XHTML 1.0 pages will be served as text/html.

We assume that, because of its tendency to cause Internet Explorer to render in quirks mode, some people prefer not to use the XML declaration for XHTML served as text/html.