XHTML (eXtensible HyperText Markup Language) is a family of XML markup languages written in XML that are the extend versions of the widely-used Hypertext Markup Language (HTML). It’s called an “eXtensible” markup language because the web developers can create their own objects and tags (Custom Tags) for each Web page they build. XHTML relies on Cascading Style Sheets (CSS) to take care of the document style. This gives the developers more control over the appearance and organization of contents in their Web pages. In order for the custom tags to work the custom tags and attributes should be defined in the Document Type Definition (DTD), that is referenced by the XHTML page. The XHTML pages appear more uniform across different browser platforms.
