js-图片预加载

//预加载
function preloader() {
if (document.images) {
var img1 = new Image();
var img2 = new Image();
var img3 = new Image();
var img4 = new Image();
img1.src = "images/lhb1.png";
img2.src = "images/lhb2.png";
img3.src = "images/lhb3.png";
img4.src = "images/lhb4.png";
}
}
function addLoadEvent(func) {
var oldonload = window.onload;
if (typeof window.onload != ‘function‘) {
window.onload = func;
} else {
window.onload = function () {
if (oldonload) {
oldonload();
}
func();
}
}
}
addLoadEvent(preloader);