Js to determine whether the method is ie summary

The third kind of test is available

The first:

if(window.addEventListener){ 
alert("not ie"); 
}else if(window.attachEvent){ 
alert("is ie"); 
}else{ 
alert(" This happens in unsupported DHTML Older versions of browsers (now generally supported) ") 
}

The second:

if(document.all){ 
alert("IE6"); 
}else{ 
alert("not ie"); 
}

The third:

var navigatorName = "Microsoft Internet Explorer"; 
var isIE = false; 
if( navigator.appName == navigatorName ){ 
isIE = true; 
alert("ie") 
}else{ 
alert("not ie") 
}

Fourth:

if(!+[1,])alert(" This is a ie The browser "); 
　　 else alert(" This is not ie The browser ");