基于jquery插件的图片有预跟无序加载

核心代码

/**
 * 图片预加载
 */
(function ($) {
 function Preload(imgs,options) {
 this.imgs = (typeof imgs === "string")?[imgs]:imgs;
 this.opts = $.extend({},Preload.DEFAULTS,options);
 // this._unoredered();
 if(this.opts.order === 'ordered'){
 this._ordered();
 }else {
 this._unoredered();
 }
 }
 Preload.DEFAULTS = {
 /**
 * 默认情况下无序的预加载
 */
 order:"unoredered",
 /**
 * 每张图片加载完毕后执行
 */
 each:null,
 /**
 * 所有图片加载完毕后执行
 */
 all:null,
 };
 Preload.prototype._ordered = function(){
 /**
 * 有序加载
 */
 var opts = this.opts,
 imgs = this.imgs,
 len = imgs.length,
 count = 0;
 load();
 function load() {
 var imgObj = new Image();
 $(imgObj).on("load error",function () {
 opts.each && opts.each(count);
 if(count >= len){
 /**
 * 所有图片已经加载完毕
 */
 opts.all && opts.all();
 }else {
 load();
 }
 count++;
 });
 imgObj.src = imgs[count];
 }
 };
 Preload.prototype._unoredered = function () {
 /**
 * 无序加载
 */
 var imgs = this.imgs,
 opts = this.opts,
 count = 0,
 len = imgs.length;
 $.each(imgs,function (i,src) {
 if(typeof src != "string") return;
 var imgObj = new Image();
 $(imgObj).on("load error",function () {
 opts.each && opts.each(count);
 if(count >= len -1){
 opts.all && opts.all();
 }
 count ++;
 });
 imgObj.src = src;
 });
 };
 $.extend({
 preload:function (imgs,opts) {
 new Preload(imgs,opts)
 }
 })
})(jQuery);