Web Design Handbook « xHTML xHTML is HTML that conforms to XML syntax: The major difference being that XML tags are nested so that every tag inside an tag is closed before the outer tag is closed and all tags need to be closed -- For example: Valid HTML <b><font face="Arial"> This is OK in HTML</b> but not in xml</font> <p>This is OK in HTML <center> <b>center this title</b><div> This can be confusing</center> It also creates a design issue, when style of center and div tags are different.</div> In xHTML <font face="Arial"><b> This is good in HTML</b> and in xml</font> <p>This is now good in HTML and xHTML</p> <center><b> center this title </b></center> <div><center>XML is less confusing</center> formating of page is always clear.</div> Wikipedia - xHTML
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