function moveOver(imgObj) {
    if (typeof window.addEventListener != "undefined") { 
        imgObj.addEventListener("mouseover",function(){imgObj.src ="images/" + imgObj.id + "_over.jpg";}, false);
        imgObj.addEventListener("mouseout", function(){imgObj.src ="images/" + imgObj.id + "_default.jpg";}, false);
    } else {
        imgObj.attachEvent("onmouseover",function(){imgObj.src ="images/" + imgObj.id + "_over.jpg";});
        imgObj.attachEvent("onmouseout", function(){imgObj.src ="images/" + imgObj.id + "_default.jpg";});
    }
}

function rollover() {
var images = document.getElementsByTagName("img");
var roll = new RegExp ("rollover");
var preload = [];
for (var i = 0; i < images.length; i++) {
    if (images[i].id.match(roll)) {
        preload[i] = new Image();
        preload[i].src =  images[i].id + "_over.jpg";
        moveOver(images[i]);
    }
}

}


if (typeof window.addEventListener != "undefined") {
    window.addEventListener("load",rollover,false);
} else {
    window.attachEvent("onload",rollover)
}