function imgSwap(oImg)
{
   var strOver  = "_on"    // image to be used with mouse over
   var strOff = "_off"     // normal image
   var strImg = oImg.src
   if (strImg.indexOf(strOver) != -1)
      oImg.src = strImg.replace(strOver,strOff)
   else
      oImg.src = strImg.replace(strOff,strOver)
}

function preloadImages() {

	image1 = new Image();
	image1.src = "";
	
	
}