var AMOUNT = 20;

 

function makeMcShake(which:MovieClip){

     which.defaultPos = {which.x, which.y}

     which.addEventListener(Event.EnterFrame, shake);

}

 

function stopMcShake(which:MovieClip){

      which.removeEventListener(Event.EnterFrame, shake);

      which.x = which.defaultPos.x;

      which.y = which.defaultPos.y;

}

 

function shake(e:Event){

    e.currentTarget.x = e.currentTarget.defaultPos.x + Math.rand() * AMOUNT - AMOUNT / 2;

    e.currentTarget.y = e.currentTarget.defaultPos.y+ Math.rand() * AMOUNT  - AMOUNT / 2;

}