function rollOver(img_name, img_src)
   {
   document[img_name].src = img_src;
   }

function rollOverTWOimages(img_name1, img_src1, img_name2, img_src2)
   {
   document[img_name1].src = img_src1;
   document[img_name2].src = img_src2;
   }
   
// PRELOAD IMAGES

var image1 = new Image();
	image1.src = "1_on.jpg";
	
var image2 = new Image();
	image2.src = "2_on.jpg";
	
var image3 = new Image();
	image3.src = "3_on.jpg";