Problem Mouseenter

Problem Mouseenter

I want to do like that

i have a center point , when i hover mouse to left of that point , slider will move left , and same with right

var margin = $("#viewer").offset().left;
       padding = $("#viewer").width()/2,
    m = margin+padding;
 
     $("#viewer").mouseenter(function(e) {
   var te = m-e.pageX;
 $('#slide').animate({left:"-="+te+"px"}) ;
  });

And

<div id="viewer">
        <div id="slide">
       
                <img id="image1" class="current" src="21.jpg" alt="Amstrad CPC 472">
                <img id="image2" src="45ew645f4sa.jpg" alt="Atari TT030">
                <img id="image3" src="4h54df54hg5a.jpg" alt="Commodore 64">
                <img id="image4" src="46eg.jpg" alt="Commodore 128">
                <img id="image5" src="4w54erwe.jpg" alt="Sinclair ZX Spectrum +2">
         </div>
       
       
         </div>          

But , it only move left / right  one time . So , how can div slider automatic move left (while mouse still hover viewer) forever until my mouse out of viewer