What is XHTML?

XHTML stands for Extensible HyperText Markup Language.

It is a language that branches off of HTML, combining the use of XML syntax with HTML markup; all tags and attributes must be lowercase, all tags must be closed, and tags must be nested properly (as to not overlap one another in a shift).

The requirements to comply with XHTML standards force the use of CSS in the place of specific tags to establish cross-browser compatibility on styles. These standards are issued by the W3C.

XHTML is compatible with all (if not, most) modern browsers.