I NEED TO INPROVE THE CODE ON A MOVIECLIP, TO CONTROL ITS PLAYING SPEED!!

Hi!

I am using this code on a movieClip to make it go from a certain frame to another (backwards or forward) depending on a global variable value. I set the global variable value by pressing buttons.
It works great!

Now: I need to control the playing speed of the movieClip, just by changing a value number directly on the code.
I believe that a 'setInterval' will work, but I don't know exactly where or how.

Can you help me?

Thanks!
Alejandro


CODE:
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// This one goes on the root frame 1. It sets the global variable.
_global.destframe=1

//This one goes on the movieClip that plays backwards or forward, depending on the global variable value.
onClipEvent (enterFrame) {
      if (this._currentframe<_global.destframe) {
            this.nextFrame();
      } else if (this._currentframe>_global.destframe) {
            this.prevFrame();
      }
}
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