index.js
function checkBug() {
    // Check if it works on newly created node (fails in IE 9)
    var a = document.createElement('div');
    if (method.call(a, 'div')) {
        return false;
    }

    // Check if it works when node is appended to another node (works in IE 9)
    var b = document.createElement('div');
    a.appendChild(b);
    return method.call(b, 'div');
}
function checkBug() {
    // Check if it works on newly created node (fails in IE 9)
    var a = document.createElement('div');
    if (method.call(a, 'div')) {
        return false;
    }

    // Check if it works when node is appended to another node (works in IE 9)
    var b = document.createElement('div');
    a.appendChild(b);
    return method.call(b, 'div');
}
Work around IE 9 bug where it always returns false when not attached to another DOM node. Check if the bug exists in this browser