JS IE Detection with conditional comments

gistfile1.js

var ieCheck = document.createElement('div');

ieCheck.innerHTML = '<!--[if lt IE 7]>IE6<![endif]--><!--[if IE 7]>IE7<![endif]--><!--[if IE 8]>IE8<![endif]--><!--[if IE 9]>IE9<![endif]-->';

if (ieCheck.innerHTML === 'IE6') {
    alert('IE6 or lower');
} else if (ieCheck.innerHTML === 'IE7') {
    alert('IE7');
} else if (ieCheck.innerHTML === 'IE8') {
    alert('IE8');
} else if (ieCheck.innerHTML === 'IE9') {
    alert('IE9');
}