原生JS检测IE版本

//检测IE版本
function cheackIE(){
var appName = navigator.appName,
userAgent = navigator.userAgent,
version;
if(appName == ''Microsoft Internet Explorer''){
version = /MSIEs(S)/.exec(userAgent)[1];
versionfloat = parseFloat(version);
return versionfloat;
}
return null;
}