This section contains a listing of all elements and attributes in HTML 4.01/XHTML 1.0 and HTML5, as well as a few nonstandard elements.
Readers are advised to watch for these labels on elements and attributes:
Elements and attributes marked as Deprecated are being phased out of HTML—usually in favor of Cascading Style Sheets—and are discouraged from use. All deprecated elements and attributes have been removed from the Strict versions of HTML 4.01 and XHTML 1.0.
Elements and attributes marked HTML5 only are new in HTML5 and may have limited or no browser support.
Attributes marked Not in HTML5 have been omitted from HTML5, usually because they are presentational or were never supported by popular browsers.
Attributes marked XHTML only apply only to documents marked up in XHTML 1.0 or 1.1. Other minor differences between HTML and XHTML are noted similarly.
Nonstandard elements and attributes are not included in any version of the HTML or XHTML Recommendations but are well supported by browsers.
Attributes marked as Required must be included in the element for the markup to be valid.