【一】用var 声明多个变量，比每个变量都用var快多了　　　

复制代码 代码如下:
var sScrollTop = document.body.scrollTop || document.documentElement.scrollTop,
sWindow_h = document.documentElement.clientHeight,
t_h = parseInt(this.getCss(this.getId('gy_photoBox_head'),'height')),
hold_h = sWindow_h - t_h - 20,
width = this.nImgWidth ,
height = this.nImgHeight;　　

【二】Dom事件优化，在 window.onresize时，定义个定时器,setTimeout，可以防止事件频繁调用

复制代码 代码如下:
windowResize:function(){
var _that = this,
_timer = null;
// 函数节流
window.onresize = function(){
clearTimeout(_timer);
_timer = setTimeout(function(){
if( _that.tools.getId('gy_photoBox')){
_that.setBoxCss();
}

},100);
}
}

【三】图片加载的处理函数
复制代码 代码如下:

imgLoading:function(opt){
var _img = new Image(),
_that = this;
_img.onload = function(){
_that.nImgWidth = this.width;
_that.nImgHeight = this.height;
if(typeof opt.success == 'function'){
setTimeout(function(){
opt.success();
},300);
}
}
_img.onerror = function(){
if(typeof opt.error){
opt.error();
}
}
// 注意：要放在onload事件下面，否则ie会出现BUG
_img.src = opt.src;
}

源代码：

复制代码 代码如下:

(function(){

var selector = function(str){
// 定义元素数组
var elem = [];

//返回是id的元素
function _getId(id){
return document.getElementById(id);
}
//返回存在此类名的元素-元素
function _getByClassName(className,parent){
var class_array = [],
node = parent != undefined&&parent.nodeType==1?parent.getElementsByTagName('*'):document.getElementsByTagName('*'),
reg = new RegExp("(^|\\s)"+className+"(\\s|$)");
for(var n=0,i=node.length;n<i;n++){
if(reg.test(node[n].className)){
class_array.push(node[n]);
}
}
return class_array;
}
//一级选择，如 '#id','p','.class'
// return [Array]
function _getDom(s){
var array_elem = [];
if (s.indexOf('#')==0){
array_elem.push(_getId(s.slice(1)));
}
else if(s.indexOf('.')==0){
array_elem = array_elem.concat(_getByClassName(s.slice(1)));
}
else{
var tag = document.getElementsByTagName(s);
for(var n=0,i=tag.length;n<i;n++){
array_elem.push(tag[n]);
}
}
return array_elem;
}

function _query(array_elem,r){
var node = array_elem,
type_name = node[0].match(/\#/)?'id_'+node[0].slice(1):node[0].match(/\./)?'className_'+node[0].slice(1):'tagName_'+node[0],
child = _getDom(node[1]),
type = type_name.split('_'),
len = document.getElementsByTagName('*').length,
reg = new RegExp("(^|\\s)"+type[1]+"(\\s|$)");;
for(var i=0,j=child.length;i<j;i++){
var par = child[i].parentNode;
for(var n=0;n<len;n++){
if(par.nodeType == 9){
break;
}
if(reg.test(par[type[0]])){
elem.push(child[i]);
break;
}else{
if(r == '>') break;
par = par.parentNode;
}
}
}
}

var elemStr = str.replace(/(^\s+)|(\s+$)/,'');
if(document.querySelectorAll){
var dom = document.querySelectorAll(elemStr);
for(var n=0,len=dom.length;n<len;n++){
elem.push(dom[n]);
}
}else{
var split = /[\>\s]/g.exec(elemStr);
if(split){
var node = elemStr.split(split[0]);
_query(node,split[0]);
}else{
elem = elem.concat( _getDom(elemStr) );
}
}
return elem;
}

function LGY_photoBox(option){
this.opt = option;
this.oTarget = typeof option.target == 'object'?option.target:selector(option.target);
if(!this.oTarget) return;
this.nLen = this.oTarget.length; //总个数
this.aBigimg_src = []; //大图数据数组
this.aTitle = []; //标题数据数组
this.nIndex = 0; //索引
this.nImgWidth = 0; //动态获取图片的宽
this.nImgHeight = 0; //动态获取图片的高
this.nDelay = 0.2;
this.intit();
}
LGY_photoBox.prototype = {
intit:function(){
var _that = this;
this.getData();
for(var n=0;n<this.nLen;n++){
this.oTarget[n].index = n;
this.oTarget[n].onclick = function(e){
_that.createCover();
var e = _that.tools.getEvent(e),
target = _that.tools.getTarget(e);
// 设置浏页面没有滚动条出现
_that.tools.setCss(document.documentElement,{'height':'100%','overflow-y':'hidden','overflow-x':'hidden'});
// 获取当时索引
_that.nIndex = this.index;
//首次判断
_that.firstLoad(_that.aBigimg_src[_that.nIndex],function(){
//插入结构
_that.createBoxDom();
//关闭
_that.tools.getId('gy_photoBox_close').onclick = function(){
_that.removeBox();
}
// 判断左右按钮显示
_that.btnIsShow();
// 上一张
_that.btnPrev();
// 下一张
_that.btnNext();
// 加载图片
_that.imgChange(_that.aBigimg_src[_that.nIndex]);
});
// 重置窗口大小
_that.windowResize();
// 键盘事件
_that.keyEvent();
//阻止跳转
return false;
}
}
},
createBoxDom:function(){
var doc = document,
exHtml = '',
boxHtml = doc.createElement('div');
boxHtml.id = 'gy_photoBox';
doc.body.appendChild(boxHtml);
if(typeof this.opt.appendHTML == 'string'){
exHtml = this.opt.appendHTML;
}
boxHtml.innerHTML = '<div id="gy_photoBox_prev"></div>'+
'<div id="gy_photoBox_next"></div>'+
'<span id="gy_photoBox_close"></span>'+
'<div id="gy_photoBox_head">'+exHtml+'</div>'+
'<div id="gy_photoBox_main">'+
'<img id="gy_photoBox_img_loading" src="http://putedStyle(node,null)[value];
},
setCss:function(node,val){
for(var v in val){
node.style.cssText += ';'+ v +':'+val[v];
}
}
}
}()
}
window.LGY_photoBox = LGY_photoBox;
})();

最终效果图：