//preload images
	
	contact = new Image(21, 19); contact.src="images/contact.gif";
	home = new Image(21, 19); home.src="images/home.gif";

	contacton = new Image(21, 19); contacton.src="images/contact_on.gif";
	homeon = new Image(21, 19); homeon.src="images/home_on.gif";

function SwitchGif(imgDocID,ImgObjName)
     {
       document.images[imgDocID].src = eval(ImgObjName + ".src")
     }