var NN4 = 1;
  var IE  = 2;
  var NN6 = 3;
  var OP  = 4;

  function getUserAgent()
    {
    if(navigator.userAgent.indexOf("Opera")!=-1)
      {
      return OP;
      }
    else
      {
      if(document.layers)
        {
        return NN4;
        }
      else
        {
        if(document.getElementById)
          {
          if(document.all)
            {
            return IE;
            }
          else
            {
            return NN6;
            }
          }
        }
      }
    }
    
  var gsUserAgent = getUserAgent()

  function setTop(obj,pos)
    {
    switch(gsUserAgent)
      {
      case IE || OP:
        obj.style.pixelTop = pos;
        break;
        
      case NN4:
        obj.top = pos;
        break;

      case NN6:
        obj.style.top = (pos - 14) + "px";
        break;

      default:
        alert('Could not set top position of ' + obj.id + '.');
        break;
      }
    }