ActionScript 2.0 :: MovieClip (Box) To Follow Mouse Click On Screen

Imagine we have a MovieClip called "box". When I click somewhere on the screen, I want the box MC to move to that position. So I wrote something like this (just for horizontal movement):

PHP Code:
onMouseDown=function(){moveTo(_xmouse);};
function moveTo(newx){box.onEnterFrame=function(){if(box._x<newx){box._x+=5;
}else if(box._x>newx){box._x-=5;}else{delete box.onEnterFrame;}};}

Now this works to a degree, except that when the box MC moves to the right position, it then proceeds to vibrate on the spot. I thought it was probably because it can never move to the exact position of _xmouse because I'm adding 10 to the x property which is why the condition is never met. However even if I just add 1 instead of 10, I still have the same problem..