if (document.images) {
		  var imagesNormal = new Object();
		  imagesNormal["nav1"] = new Image(189,75);
		  imagesNormal["nav1"].src = "images/nav1.gif";
		  imagesNormal["nav2"] = new Image(189,75);
		  imagesNormal["nav2"].src = "images/nav2.gif";
		  imagesNormal["nav3"] = new Image(189,75);
		  imagesNormal["nav3"].src = "images/nav3.gif";
		  imagesNormal["nav4"] = new Image(188,75);
		  imagesNormal["nav4"].src = "images/nav4.gif";
		  var imagesHilite = new Object();
		  imagesHilite["nav1"] = new Image(189,75);
		  imagesHilite["nav1"].src = "images/hnav1.gif";
		  imagesHilite["nav2"] = new Image(189,75);
		  imagesHilite["nav2"].src = "images/hnav2.gif";
		  imagesHilite["nav3"] = new Image(189,75);
		  imagesHilite["nav3"].src = "images/hnav3.gif";
		  imagesHilite["nav4"] = new Image(188,75);
		  imagesHilite["nav4"].src = "images/hnav4.gif";
	  }

      function RollOn(imgName){
	      document.images[imgName].src = imagesHilite[imgName].src;
	      return true;
      }
      function RollOff(imgName){
	      document.images[imgName].src = imagesNormal[imgName].src;
	      return true;
      }