What is the status of the HTML 5 standard?
The HTML 5 standard is still under development. However, to extend the life span of HTML documents being created, it's not a bad idea to start migrating toward those features of HTML 5 that already work now. A good place to start is the HTML Cheat Sheet. Avoid any obsolete coding that is shown with a strikethrough font and be aware than anything indicated as New features in HTML 5 might not work in some browsers yet.
When can I start coding with HTML 5?
HTML 5 has been designed to be relatively backward compatible with both the 1997-1999 HTML 4 standard and the 2000-2001 XHTML 1.x W3C recommendation of HTML. The XML serialization of HTML 5 merges these two standards, and is already understood by virtually all web browsers including XHTML-based mobile browsers. Polyglot HTML documents can be delivered either as text/html to traditional web browsers or as application/xhtml+xml to web browsers on computers as well as in cell phones and other handheld devices. So if you start creating polyglot documents now your web pages will be well positioned for both current and future HTML browsers and mobile devices. For now, just try to avoid tags that have been deprecated in HTML 5 or newly added - the HTML Cheat Sheet is designed to help with both what's new in HTML 5 and what's been deprecated. Make sure you know how to use CSS and XSL templates.
What is the easiest way to make the transition to HTML 5?
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What are some advantages/disadvantages of the HTML serialization vs. the XML serialization of HTML 5?
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