if (document.images) {    
        
        
      img1on = new Image();
            img1on.src = "images/homehot.gif";    					  
            img2on = new Image();
            img2on.src = "images/servhot.gif";
            img3on = new Image();
            img3on.src = "images/suphot.gif";
        	img4on = new Image();
            img4on.src = "images/conhot.gif";
            
           
            img1off = new Image(); 								
            img1off.src = "images/homereg.gif";
            img2off = new Image(); 								
            img2off.src = "images/servreg.gif";
            img3off = new Image();
            img3off.src = "images/supreg.gif";
            img4off = new Image();
            img4off.src = "images/conreg.gif";
           
			}

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

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