HTML and XHTML Element Reference - HTML and CSS: The Complete Reference - page 167

Standard Syntax
<acronym
class="class name(s)"
dir="ltr | rtl"
id="unique alphanumeric identifier"
lang="language code"
style="style information"
title="advisory text">

</acronym>

Attributes Defined by Internet Explorer
accesskey="key" (5.5)
contenteditable="false | true | inherit" (5.5)
disabled="false | true" (5.5)
hidefocus="true | false" (5.5)
language="javascript | jscript | vbs | vbscript" (4)
tabindex="number" (5.5)
unselectable="off | on" (5.5)

HTML 4 Event Attributes
onclick, ondblclick, onkeydown, onkeypress, onkeyup, onmousedown,
onmousemove, onmouseout, onmouseover, onmouseup

Events Defined by Internet Explorer
onactivate, onbeforedeactivate, onbeforeeditfocus, onblur, onclick,
oncontrolselect, ondblclick, ondeactivate, ondrag, ondragend, ondragenter,
ondragleave, ondragover, ondragstart, ondrop, onfocus, onkeydown, onkeypress,
onkeyup, onhelp, onmousedown, onmouseenter, onmouseleave, onmousemove,
onmouseout, onmouseover, onmouseup, onmove, onmoveend, onmovestart,
onreadystatechange, onresizeend, onresizestart, onselectstart, ontimeerror

Examples
<p><acronym title="Extensible Markup Language"> XML </acronym>

<acronym lang="fr" title="Soci&eacute;t&eacute; Nationale de Chemins de
Fer"> SNCF </acronym></p>

Compatibility

HTML 4, 4.01
XHTML 1.0, 1.1, Basic

Firefox 1+, Internet Explorer 4+,
Netscape 6+, Opera 6+, Safari 1+

Notes
• This tag is often confused with <abbr> and is not included in HTML5 as of late 2009.
• As with an <abbr> tag, most browsers will render a dotted underline when the title
attribute is present.
• Errors may occur in the MSDN documentation for this element; for example,
disabled continues to be supported and many events not documented will work.