if (document.images) 
{
      img1 = new Image();
      img2 = new Image();
      img3 = new Image();
      img4 = new Image();
      img5 = new Image();
      img1.src ="../images/tab_map_over.gif"; 
      img2.src ="../images/tab_photos_over.gif"; 
      img3.src ="../images/tab_rentalHistory_over.gif";
      img4.src ="../images/tab_saleHistory_over.gif"; 
      img5.src ="../images/tab_talkback_over.gif"; 
}