HTML Reference (Webmaster in a Nutshell, 3rd Edition)

3.1. Core Attributes

Prior to HTML Version 4, there were few attributes that could be used consistently for all HTML tags. HTML 4 changes this, defining a set of 16 core attributes that can be applied to almost all the tags in the language. For brevity, we list these core attributes in this section and spare you the redundancies in the table that follows:

class=name: Specify a style class controlling the appearance of the tag's contents.
dir=dir: Specify the rendering direction for text, either left to right (ltr) or right to left (rtl).
id=name: Define a reference name for the tag that is unique in the document.
lang=language: Specify the human language for the tag's contents with an ISO639 standard two-character name and optional dialect subcode.
onclick=applet: Specify an applet to be executed when the user clicks the mouse on the tag's contents display area.
ondblclick=applet: Specify an applet to be executed when the user double-clicks the mouse button on the tag's contents display area.
onkeydown=applet: Specify an applet to be executed when the user presses down on a key while the tag's contents have input focus.
onkeypress=applet: Specify an applet to be executed when the user presses and releases a key while the tag's contents have input focus.
onkeyup=applet: Specify an applet to be executed when the user releases a pressed key while the tag's contents have input focus.
onmousedown=applet: Specify an applet to be executed when the user presses down on the mouse button when pointing to the tag's contents display area.
onmousemove=applet: Specify an applet to be executed when the user moves the mouse in the tag's contents display area.
onmouseout=applet: Specify an applet to be executed when the user moves the mouse off the tag's contents display area.
onmouseover=applet: Specify an applet to be executed when the user moves the mouse into the tag's contents display area.
onmouseup=applet: Specify an applet to be executed when the user releases the mouse button when in the tag's contents display area.
style=style: Specify an inline style for the tag.
title=string: Specify a title for the tag.

A small handful of tags do not accept all of these attributes. They are:

<applet>      <embed>      <html>      <marquee>      <script>
<base>        <font>       <iframe>     <meta>        <server>
<basefont>    <frame>      <ilayer>     <multicol>    <spacer>
<bdo>         <frameset>   <isindex>    <nobr>        <style>
<br>          <head>       <keygen>     <noembed>     <title>   
<comment>     <hr>         <layer>      <param>       <wbr>

In the reference section, we list all the attributes supported by these special tags, including the common ones. For all other tags, assume the common attributes in the preceding list apply.

Chapter 3. HTML Reference

Contents:

3.1. Core Attributes