session失效刷新后登录页面嵌入在iframe中的解决办法

var _topWin = window;  
while (_topWin != _topWin.parent.window) {  
     _topWin = _topWin.parent.window;  
}  
if (window != _topWin)_topWin.document.location.href = '${base}/main/login';