jQuery shim to focus on any element regardless of tabindex

jquery.focus-shim.js

/* jquery shim to focus on any element regardless of tabindex */
(function($) {
    $.fn.focus = (function(focus) {
        return function () {
            if (arguments.length > 0) {
                return focus.apply(this, arguments);
            }
            if (typeof $(this).attr('tabindex') === 'undefined') {
                return focus.call(this.attr('tabindex', '-1')).removeAttr('tabindex');
            }
            return focus.call(this);
        };
    })($.fn.focus);
})(jQuery);