function bgChange(elemID, dir, Pos){
    
    var element = document.getElementById(elemID);
    
    if (element != null){
        switch (dir)
        { case "x": 
          element.style.backgroundPosition = Pos + 'px 0px';
          break;
          case "y":
          element.style.backgroundPosition = '0px ' + Pos + 'px';
          break; } 
     }
    
    }
    
    function bgReset(elemID){
    var element = document.getElementById(elemID);
    if (element != null){
    element.style.backgroundPosition = '0px 0px';
    }
    }