How to implement html nested iframe to wait for the iframe page to load before calling the next step_html/css_WEB-ITnose

我就用代码来解释一个例子吧：

<div align="left" style="height: 100%" id ="benefitnotice_report">	<iframe id="benefitnotice_iframe" width="100%" height="90%" frameborder="0" >	</iframe></div>

	var id ="#benefitnotice_report";		showWaiting('正在加载报表' , null, id);//遮罩层调用		src=src+"&aic1621="+aic1621+"&aic1622="+aic1622+"&aae140="+aae140+"&aaf101="+aaf101+"&aaz070="+aaz070+"&aac031="+aac031;						$("#benefitnotice_iframe").attr("src",src);

	$("#benefitnotice_iframe").load(function(){           closeWaiting("#benefitnotice_report");    });