if (document.images) {        
imgXon = new Image();      // Std MouseOver Images
imgXon.src = " ";

imgXoff = new Image();
imgXoff.src = " ";        // Std MouseOut Images

}


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");
}}