Image rollover problem - using div layers

function showByShadow(object,shadow,x,y) {
    if (document.layers && document.layers[object]) {
        document.layers[object].left = document.layers[shadow].pageX + x;
        document.layers[object].top = document.layers[shadow].pageY + y;
        document.layers[object].visibility = 'visible';
    }
    else if (document.all) {
        document.all[object].style.visibility = 'visible';

        if (document.all[object].myFlag == null) {
            document.all[object].style.posLeft = document.all[object].offsetLeft + x;
            document.all[object].style.posTop = document.all[object].offsetTop + y;
    		document.all[object].myFlag = true;
        }
    }
}

function hide(object) {
    if (document.layers && document.layers[object])
        document.layers[object].visibility = 'hidden';
    else if (document.all)
        document.all[object].style.visibility = 'hidden';
}