dtree加载慢的问题

　　前几天测试的时候，感觉dtree还行，也不是很慢。今天把树分支扩大以后就懵逼了，慢的一匹。

　　

　　仔细看了下，才发现原来画分支的时候每次都会请求那些图，反复请求下加载时候无形拉长了很多。没有办法，就只能在html中提前加载好，然后js去get图片src。

　　html部分：

<div style = "display:none;">
      <img id = "plus" src = "../images/PPS/dtree_imgs/plus.gif"/>
      <img id = "empty" src = "../images/PPS/dtree_imgs/empty.gif"/>
      <img id = "line" src = "../images/PPS/dtree_imgs/line.gif"/>
      <img id = "join" src = "../images/PPS/dtree_imgs/join.gif"/>
      <img id = "page" src = "../images/PPS/dtree_imgs/page.ico"/>
      <img id = "joinbottom" src = "../images/PPS/dtree_imgs/joinbottom.gif"/>
      <img id = "plusbottom" src = "../images/PPS/dtree_imgs/plusbottom.gif"/>
      <img id = "folder-open" src = "../images/PPS/dtree_imgs/folder-open.ico"/>
      <img id = "folder-close" src = "../images/PPS/dtree_imgs/folder-close.ico"/>
      <img id = "details" src = "../images/PPS/details.ico"/>
 </div>

　　js部分:

this.icon = {

        root: '/images/PPS/dtree_imgs/base.ico',

        folder: $('#folder-close')[0].src,

        folderOpen: $('#folder-open')[0].src,

        node: $('#page')[0].src,

        empty: $('#empty')[0].src,

        line: $('#line')[0].src,

        join: $('#join')[0].src,

        joinBottom: $('#joinbottom')[0].src,

        plus: $('#plus')[0].src,

        plusBottom: $('#plusbottom')[0].src,

        minus: '/images/PPS/dtree_imgs/minus.gif',

        minusBottom: '/images/PPS/dtree_imgs/minusbottom.gif',

        nlPlus: '/images/PPS/dtree_imgs/nolines_plus.gif',

        nlMinus: '/images/PPS/dtree_imgs/nolines_minus.gif'

    };

　　改完就快多了：