Ext.Window动态修改html

bodyWin = new Ext.Window({  
		renderTo: Ext.getBody(),
		title: "支路分时统计", 
		border:false,
		closable:false,
		resizable:false,
		draggable :false,
		maximizable:true, 
		shadow: false,
		width: document.body.clientWidth - 284,
		height:document.body.clientHeight - 70,
		x:283,
		y:65,
		html:"<iframe src='<%=path%>/page/statistics/branchEnergy/branchTimeEnergy.jsp' height='100%' width='100%'></iframe>"
	});

动态修改html：

bodyWin.update("<iframe src='<%=path%>/page/emcBranchAnalysis_submitContent' height='100%' width='100%'></iframe>");

PS：在网上找过一些资料，说的都是通过load方法来实现，但试过后没有效果！