if (document.images) {
            img1on = new Image(); 
            img1on.src = "images_new/nav.membercom.on.gif";   
            img2on = new Image();
            img2on.src = "images_new/nav.bod.on.gif";
            img3on = new Image();
            img3on.src = "images_new/nav.govdocs.on.gif";
            img4on = new Image();
            img4on.src = "images_new/nav.ibis.on.gif";
            img5on = new Image();
            img5on.src = "images_new/nav.programs.on.gif";
			img6on = new Image(); 
            img6on.src = "images_new/nav.calendar.on.gif";  
			img7on = new Image(); 
            img7on.src = "images_new/nav.traveltrade.on.gif";  
		  
            img1off = new Image(); 
            img1off.src = "images_new/nav.membercom.off.gif";   
            img2off = new Image();
            img2off.src = "images_new/nav.bod.off.gif";
            img3off = new Image();
            img3off.src = "images_new/nav.govdocs.off.gif";
            img4off = new Image();
            img4off.src = "images_new/nav.ibis.off.gif";
            img5off = new Image();
            img5off.src = "images_new/nav.programs.off.gif";
			img6off = new Image(); 
            img6off.src = "images_new/nav.calendar.off.gif";  
			img7off = new Image(); 
            img7off.src = "images_new/nav.traveltrade.off.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");
        }
}