HTML 4, HTML 5, XHTML, MIME types - the definitive resource
- by deceze
The topics of HTML vs. XHTML and XHTML as text/html vs. XHTML as XHTML are quite complex. Unfortunately it's hard to get a complete picture, since information is spread mostly in bits and pieces around the web or is buried deep in W3C tech jargon. In addition there's some misinformation being circulated. I propose to make this the definite SO resource about the topic, describing the most important aspects of:
HTML 4
HTML 5
XHTML 1.0/1.1 as text/html
XHTML 1.0/1.1 as XHTML
What are the practical implications of each?
What are common pitfalls?
What is the importance of proper MIME types for each?
How do different browsers handle them?
I'd like to see one answer per technology. I'm making this a community wiki, so rather than contributing redundant answers, please edit answers to complete the picture. Feel free to start with stubs. Also feel free to edit this question.