image1_on = new Image;
   image1_off = new Image;
   image2_on = new Image;
   image2_off = new Image;
   image3_on = new Image;
   image3_off = new Image;
   image4_on = new Image;
   image4_off = new Image;
   image5_on = new Image;
   image5_off = new Image;
  
   image1_on.src = "images/img_o_04.gif"
   image1_off.src = "images/img_04.gif"
   image2_on.src = "images/img_o_06.gif"
   image2_off.src = "images/img_06.gif"
   image3_on.src = "images/img_o_08.gif"
   image3_off.src = "images/img_08.gif"
   image4_on.src = "images/img_o_10.gif"
   image4_off.src = "images/img_10.gif"
   image5_on.src = "images/img_o_12.gif"
   image5_off.src = "images/img_12.gif"