获得顶层窗口 _Web前端

取得顶层窗口
var isTopOtherSystem = false;//最上层窗口是不是本系统
	//返回层级窗口
		function findOpenerWin(win){
				var openerWin = win.top.dialogArguments;				
				if (!openerWin){
						openerWin = win.top.opener;					
				}
				if (openerWin){
					try
					{
							openerWin.top.document.location;
					}
					catch(e)
					{					
							isTopOtherSystem = true;										  		
					}			
					if (isTopOtherSystem){
						return openerWin;
					}
					return findOpenerWin(openerWin)
				}
				else{
					try
					{
//可能产生跨域异常
							win.top.document.location;
					}
					catch(e)
					{					
							isTopOtherSystem = true;										  		
					}			
				}
				return win;
		}