如何用Javascript检测到所有的IE版本

function GetIEVersion() {

var sAgent = window.navigator.userAgent;

var Idx = sAgent.indexOf("MSIE");

?

// If IE, return version number.

if (Idx > 0)

return parseInt(sAgent.substring(Idx+ 5, sAgent.indexOf(".", Idx)));

?

// If IE 11 then look for Updated user agent string.

else if (!!navigator.userAgent.match(/Trident\/7\./))

return 11;

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else

return 0; //It is not IE

}

?

if (GetIEVersion() > 0)

alert("This is IE " + GetIEVersion());

else

alert("This is not IE.");