Question

What would be your fastest, shortest (best) way to detect browser which is IE and version less than 9 in JavaScript, without using jQuery or any add-on libraries?

Answer 1

Javascript

var ie = (function(){

    var undef,
        v = 3,
        div = document.createElement('div'),
        all = div.getElementsByTagName('i');

    while (
        div.innerHTML = '<!--[if gt IE ' + (++v) + ']><i></i><![endif]-->',
        all[0]
    );

    return v > 4 ? v : undef;

}());

You can then do:

ie < 9

By James Panolsey from here: http://james.padolsey.com/javascript/detect-ie-in-js-using-conditional-comments