// 使用Dom方法创建覆盖层和高亮层
function addLightboxMarkup() {
        bod = document.getElementsByTagName('body')[0];
        overlay = document.createElement('div');
        overlay.id = 'overlay';
        lb = document.createElement('div');
        lb.id = 'lightbox';
        lb.className = 'loading';
        lb.innerHTML = '<div id="lbLoadMessage">' +
                                           '<p>Loading</p>' +
                                           '</div>';
        bod.appendChild(overlay);
        bod.appendChild(lb);
}
封装lightbox类
初始化数据时，为每个可高亮显示的链接创建了lightbox对象。该类的代码具体实现如下：
var lightbox = Class.create(); 

lightbox.prototype = {
       yPos : 0,
       xPos : 0,
      //构造方法,ctrl为创建该对象的元素
       initialize: function(ctrl) {
              //将该元素的链接赋值给this.content
              this.content = ctrl.href;
              //为该元素添加onclick事件activate方法
              Event.observe(ctrl, 'click', this.activate.bindAsEventListener(this), false);
              ctrl.onclick = function(){return false;};
       },

       //当单击链接时
       activate: function(){
              if (browser == 'Internet Explorer'){//判断为IE浏览器
                     this.getScroll();
                     this.prepareIE('100%', 'hidden');
                     this.setScroll(0,0);
                     this.hideSelects('hidden');//隐藏所有的<select>标记
              }
              //调用该类中的displayLightbox方法
              this.displayLightbox("block");
      },