if (document.images) {
                  
            img1on = new Image(); 
            img1on.src = "images/navoff.1_over.gif";   
            img2on = new Image();
            img2on.src = "images/navoff.2_over.gif";
            img3on = new Image();
            img3on.src = "images/navoff.3_over.gif";
            img4on = new Image();
            img4on.src = "images/navoff.4_over.gif";
            img5on = new Image();
            img5on.src = "images/navoff.5_over.gif";
            img6on = new Image();
            img6on.src = "images/navoff.6_over.gif";
            img7on = new Image();
            img7on.src = "images/navoff.7_over.gif";
		  
            img1off = new Image(); 
            img1off.src = "images/navoff.1.gif";   
            img2off = new Image();
            img2off.src = "images/navoff.2.gif";
            img3off = new Image();
            img3off.src = "images/navoff.3.gif";
            img4off = new Image();
            img4off.src = "images/navoff.4.gif";
            img5off = new Image();
            img5off.src = "images/navoff.5.gif";
            img6off = new Image();
            img6off.src = "images/navoff.6.gif";
            img7off = new Image();
            img7off.src = "images/navoff.7.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");


        }
}