I'm intrested in finding out if a client watched an entire video,
and i was wondering if it is possible using JS or any other client-side language?
and if not what would be the best approach?

Thanks in advance,

How are you embedding the video into the page? If you are using Flash, there are ways to trigger events to update form values once a video has come to its end.

But if the client will drag the player near the end the event will still trigger,no?
or is it possible to disable forwarding in Flash player?

It depends, I guess, on the Flash player that you are using. Many "out-of-the-box" solutions do not allow for hiding the scrub bar. If you are building the player yourself, it is absolutely possible, as I have done it in the past.

If you are using the FLVPlayback component in Flash, you can go to the component inspector and choose "SkinOverPlayFullscreen" from the skins that will allow the player controls to display only the Play button and the fullscreen button. There are other skins that do not contain the scrubber bar, so you could choose one of them, or even create your own.

I'm pretty sure you could get more detailed advice if this subject were moved to the Flash forums. If a mod happens to see this, it might be more helpful to Eric to move this topic there.

Hope this helps. My 2ยข.