nice function to detect IE

detectIE.js

function detectIE(){
    var ua = window.navigator.userAgent;
    var msie = /MSIE/.test( ua );
    var trident = /Trident/.test( ua );

    if( msie > 0 ){
        // IE 10 or older => return version number
        var msiePosition = ua.indexOf('MSIE ')+5;
        return parseInt( ua.replace(/.*MSIE ([0-9]+).*/,'$1') ); // Return only the version
    }

    if( trident > 0 ){
        // IE 11 (or newer) => return version number
        return parseInt(ua.replace(/.*rv:([0-9]+).*/,'$1'), 10);
    }

    if( trident || msie ){
        return true;
    }

    // other browser
    return false;
}