function something()
{
   var divclasses = ['one','two','three'];
   function randOrd(){return (Math.round(Math.random())-0.5); }
   divclasses.sort(randOrd);
   for (var i =0; i<=2; i++) 
   {
      document.getElementById('product' + (i+1)).className = divclasses[i];
   }
}
onload = something;