if (document.images) {
        var xspecon = new Image();
        xspecon.src = "images/xspecbon.gif";
        var xspecoff = new Image();
        xspecoff.src = "images/xspecboff.gif";
		}

function rollon(imgName) {
    if (document.images) 
        document[imgName].src = eval(imgName + 'on.src');}

function rolloff(imgName) {
    if (document.images) 
        document[imgName].src = eval(imgName + 'off.src');
}