<div tooltip="Stop <font color=red>now</font>">Text text</div>Any HTML elements in Jenkins can get a tooltip by just having the tooltip attribute. The attribute value can be HTML, but all the mark up needs to be escaped so that the Jelly script still parses as XML. The actual tooltip functionality is provided by YUI. See the example below:
<div tooltip="Stop <font color=red>now</font>">Text text</div>