js解决EasyUI页面渲染速度慢问题(Mask遮罩)

/**  
 *  页面加载等待页面  
 *  
 * @author gxjiang  
 * @date 2010/7/24  
 *  
 */  
 var height = window.screen.height-250;   
 var width = window.screen.width;   
 var leftW = 300;   
 if(width>1200){   
    leftW = 500;   
 }else if(width>1000){   
    leftW = 350;   
 }else {   
    leftW = 100;   
 }   
    
 var _html = "<div id='loading' style='position:absolute;left:0;width:100%;height:"+height+"px;top:0;background:#E0ECFF;opacity:0.8;filter:alpha(opacity=80);'>\   
 <div style='position:absolute;  cursor1:wait;left:"+leftW+"px;top:200px;width:auto;height:16px;padding:12px 5px 10px 30px;\   
 background:#fff url(/wlzl/js/themes/default/images/pagination_loading.gif) no-repeat scroll 5px 10px;border:2px solid #ccc;color:#000;'>\   
 正在加载，请等待...\   
 </div></div>";   
    
 window.onload = function(){   
    var _mask = document.getElementById('loading');   
    _mask.parentNode.removeChild(_mask);   
 }   
  
        
 document.write(_html);