HTML elements, attributes, events, color names, entities, character-sets, URL encoding, language codes, HTTP messages, browser support, and more:

ref_keyboardshortcuts.asp

ref_pxtoemconversion.asp

ref_httpmethods.asp

ref_httpmessages.asp

ref_country_codes.asp

ref_language_codes.asp

ref_urlencode.asp

ref_html_dtd.asp

ref_charactersets.asp

ref_av_dom.asp

ref_canvas.asp

Elements.asp

ref_bycategory.asp

ref_html_browsersupport.asp

ref_attributes.asp

ref_standardattributes.asp

ref_eventattributes.asp

ref_colornames.asp