It's amazing how many developers claim to be proficient programming with XML, yet do not understand the basic differences between XML and HTML. Anyone with a fundamental grasp of XML should be able describe some of the main differences outlined in the table below.
Differences Between XML and HTML
XML
User definable tags
HTML
Defined set of tags designed for web display
Content driven
HTML
Format driven
End tags required for well formed documents
HTML
End tags not required
Quotes required around attributes values
HTML
Quotes not required
Slash required in empty tags
HTML
Slash not required