if (document.images) {
           pic2on = new Image(250, 46);
           pic2on.src = "img/logintoitwc_on.jpg";           

           pic2off = new Image(250, 46);
           pic2off.src = "img/logintoitwc_off.jpg";
       }

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

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