if (document.images) {

        img1on = new Image();
        img1on.src = "/images/nav_di_work_on.gif";
        img1off = new Image();
        img1off.src = "/images/nav_di_work_off.gif"
				
        img2on = new Image();
        img2on.src = "/images/nav_writ_cons_on.gif";
        img2off = new Image();
        img2off.src = "/images/nav_writ_cons_off.gif"
				
        img3on = new Image();
        img3on.src = "/images/nav_workshops_on.gif";
        img3off = new Image();
        img3off.src = "/images/nav_workshops_off.gif"
				
        img4on = new Image();
        img4on.src = "/images/nav_books_on.gif";
        img4off = new Image();
        img4off.src = "/images/nav_books_off.gif"
				
        img5on = new Image();
        img5on.src = "/images/nav_essays_on.gif";
        img5off = new Image();
        img5off.src = "/images/nav_essays_off.gif"
				
}
function imgSwap (imgName,imgFile)  { 
        if (document.images)  {
                document.images[imgName].src = eval (imgFile + ".src");
        }
}