js函数执行问题
执行一个比较耗时的函数,想在函数执行的时候用div显示一个提示信息,但是实际运行的时候div却无法显示出来,如果函数执行前alert一个对话框是可以看到div的,该怎么办啊?? 
 代码下:   
 	function   DownExcelTemplate() 
 	{ 
 		WaitDiv.Msg   =    "正在生成Excel模版,请稍候... "; 
 		WaitDiv.ShowMsg();  		 
 		//一些验证代码  		 
 		if(pa.length   ==   0) 
 		{ 
 			alert( "请先选择项目然后下载模版! ");	//如果执行到这里可以看到div 
 			WaitDiv.HiddenMsg(); 
 			return   false; 
 		}  		 
 		CreateExcelTemplate(pa);	//生成Excel,比较耗cpu,执行时我的机器大约占到60%  		 
 		WaitDiv.HiddenMsg(); 
 		return   false; 
 	}
------解决方案--------------------我是这么用的  
 html部分: 
  <div id= 'div1 ' style= 'visibility:hidden '>  
 			 <label> 正在上传,请稍后... </label>   
  </div>    
 在做复杂处理的时候,调用 js   
 div1.style.visibility=\ "visible\ "; //div显示 
 ...(做复杂处理)    
 用着还可以了,你试试吧
------解决方案-------------------- <html>    
  <head>  
  <meta http-equiv= "Content-Type " content= "text/html; charset=gb2312 ">  
  <title> 信息提示 </title>  
  </head>  
  <script language= "javascript ">  
 function show() 
 { 
 	document.getElementById( "loading ").style.display= " "; 
 	document.getElementById( "backloading ").style.display= " "; 
 } 
 function clos() 
 { 
 	document.getElementById( "loading ").style.display= "none "; 
 	document.getElementById( "backloading ").style.display= "none "; 
 } 
  </script>  
  <body style= "margin:0px;padding:0px;font-size:12px;overflow-y:hidden;z-index:0; " >    
  <div id= "loading " style= "background:#FFFFFF;color:#FFF;width:482px;height:110px;padding-left:5px;position: absolute;line-height:22px;z-index:30;display:none;margin-top:expression(body.clientHeight/2-110/2);margin-left:expression(body.clientWidth/2-482/2); ">  
  <table border= "1 " width= "482 " cellspacing= "1 " style= "border-collapse: collapse " bordercolor= "#D8DDFE " align= "center ">  
 	 <tr>  
 		 <td bgcolor= "#D8DDFE "> 信息提示 </td>  
 	 </tr>  
 	 <tr>  
 		 <td height= "54 ">  <span class= "swTit "> 测试按钮 </span>  </td>  
 	 </tr>  
 	 <tr>  
 		 <td align= "center " bgcolor= "#C0C0C0 ">  <span onclick= "clos() "> 关闭 </span>  </td>  
 	 </tr>  
  </table>  
  </div>  
  <div id= "backloading " style= "width:100%;height:100%;position:absolute;z-index:20;border:0px;background-color:#cccccc;filter:alpha(opacity=50);display:none; "align= "center ">  </div>    
  <form method= "POST " action= "--WEBBOT-SELF-- ">  
 	 <p>   </p>  
 	 <p>   </p>  
 	 <p>  <input type= "button " value= "按钮 " name= "B3 " onclick= "show() ">  </p>  
 	 <p>   </p>  
  </form>    
  </body>    
  </html>
------解决方案--------------------可以用setTimeOut()延缓执行CreateExcelTemplate(pa)的时间