if (document.images)
   {
	//img1
	 logosg_homepageon= new Image(196,49);
	 logosg_homepageon.src="_images/logosg4frontpage4b.png";  

	 logosg_homepageoff= new Image(196,49);
	 logosg_homepageoff.src="_images/logosg4frontpage4.png";

	 //img2
   }

function lightup(imgName)
 {
   if (document.images)
    {
      imgOn=eval(imgName + "on.src");
      document[imgName].src= imgOn;
    }
 }

function turnoff(imgName)
 {
   if (document.images)
    {
      imgOff=eval(imgName + "off.src");
      document[imgName].src= imgOff;
    }
 }