setInterval

Hello,
I was wondering if you could help me out.
I have thisbit of code…When you roll over the “scrubber_mc” it updates a text field called “time”. The problem is that you have to rollOut and then roll back onto the “scrubber_mc” to update the “time” text field.
What I would like is for “pos” to be triggered by setInterval so the it updates as I move along the “scrubber_mc”, so I don’t have to move off and on again.

scrubber_mc.onRollOver = function() {
var pos = this._xmouse/100;
snd.position = Math.min(snd._sound.duration, pos*snd._sound.duration/snd.loaded);
time.text = formatTime(snd.position);
};

Thankyou for any help.
M