关于获取iframe中多层嵌套问题

function close_win()
{ 
	var currentWin = window.frames["right"].frames["leftframe"].frames["son_iframe"].frames["leftframe"];
	var doc = currentWin.document.getElementById('voucherflag').value;
	var saveflag = currentWin.document.getElementById('saveflag').value;
	if(doc=='voucherflag'){
	  if(saveflag==''){
		alert('请保存当前数据信息!');
	 }else{
	   document.getElementById("index").src ="";
	 }
	}else{
	  document.getElementById("index").src ="";
	}
	//location.reload(); //页面刷新
}