HoverAttribute is a jQuery plugin that allows you to make (link-)elements more dynamic by making an attribute of that element show up on hovering. This is foremost intended for <a> tags residing within full-width elements, such as headings or list entries. Amongst several options, it is possible to choose any attribute (href by default, see Usage) of a given tag.
via HoverAttribute jQuery plugin – afEkenholm Web Design. Really cool jQuery plugin, used it for a project at work where a tooltip was not the desired tool to show additional data. It works on any jQuery object and let’s display any attribute.