Appendix AElements and Attributes A HTML Elements and Attributes This appendix contains an alphabetical listing of all elements and attributes in the HTML 4.01 and XHTML Recommendations, as well as a few nonstandard elements that are well-supported by current browsers. Elements and attributes marked as "Deprecated" have been removed from the (X)HTML Strict DTDs and are discouraged from use, usually in favor of Cascading Style Sheets. Attributes marked as "Required" must be included in the element for the markup to be valid.