If you visit any video on YouTube while not logged in, check out the textarea where you can post a comment. As you mouse-over the box, the textarea is disabled and a DIV window saying to "Register or Log In" is displayed over the textarea box.
I viewed the source and they're using an onfocus and onblur on the textarea to display the DIV which is located just below the textarea. This makes perfect sense, what I'm having a hard time with is how to position the div directly over the textarea disabling the textarea in the process. Any help on this would be greatly appreciated.