if (document.images) 
{
	image1on = new Image();
	image1on.src = "nav/on_about.gif";

	image2on = new Image();
    image2on.src = "nav/on_diagnosticforms.gif";

	image3on = new Image();
    image3on.src = "nav/on_location.gif";

	image4on = new Image();
    image4on.src = "nav/on_contact.gif";

		
    image1off = new Image();
    image1off.src = "nav/off_about.gif";

	image2off = new Image();
    image2off.src = "nav/off_diagnosticforms.gif";

	image3off = new Image();
    image3off.src = "nav/off_location.gif";

    image4off = new Image();
    image4off.src = "nav/off_contact.gif";

 
}

function changeImages() 
{
      if (document.images)
      {
             for (var i=0; i<changeImages.arguments.length; i+=2)
             {
               document[changeImages.arguments[i]].src =
               eval(changeImages.arguments[i+1] + ".src");
             }
       }
}