Video Rewind Button

I am developing a portal to watch a very long video. Is there a Java script that I can add to a button that will "rewind" the video, say 15 seconds from the point that the button is depressed? I am trying to avoid using cue points to do so because I have cue points set-up for another task.

Another way to go, would be if the seekbar is able to be dragged backwards only. Currently, as I understand it, it is "read only" or draggable forward and back. Is it possible to finagle the seekbar to be draggable backwards only?

Any help is greatly appreciated. Thanks All...