2. Extensible Hypertext Markup Language A successor to HTML 4.01 XML-compliant W3C is improving and expanding

3. Hypertext Markup Language Can handle coding errors and quirks Integrates markup features toward modern Web usage W3C is improving and expanding

4. AspectHTMLXHTML Tag Nesting May be closed out of order Must be closed in the order opened Tag Case May be written in upper or lower case Must be written in lower case Tag Closure May be omitted for some elements Must be matched with closing tags Attribute-Value Pairs May occur without attribute name Attribute-value pair required Empty Elements Do not need to be closed Must be closed Script and Style Elements May be placed within quotes Must be in separate documents and lined to XHTML document Character Codes for Special Characters Codes recommendedCodes required

5. Parallel languagesW3C improving and expanding bothUser preference depending on specific projectsEach has similar, distinct applications