Feature detection for IEs

detect-ie.js

// http://stackoverflow.com/questions/10964966/detect-ie-version-prior-to-v9-in-javascript
// http://tanalin.com/en/articles/ie-version-js/
var ie = (function (){
    if (window.ActiveXObject === undefined) return null;
    if (!document.querySelector) return 7;
    if (!document.addEventListener) return 8;
    if (!window.atob) return 9;
    if (!document.__proto__) return 10;
    return 11;
})();