You hover over a target element, then some content shows up. It should be flexible enough to customize the look and feel without requiring the bloat of any CSS or images. Hover targets should be mapped to their content counterparts by convention. I think I’ve built just that with the
The clueTip plugin allows you to easily show a fancy tooltip when the user's mouse hovers over (or, optionally, clicks on) any element you designate in your script. If the element includes a title attribute, its text becomes the heading of the clueTip.
This is Twitter-likechars counter example using MooTools.It is counter decreases, from the max value of available chars in the input field (20 in this example) to zero, while you type something into the input field.