(function($){
    $.shortcutSequence = function(sequence, callback){
            var expectedNextIndex = 0;
            $(document).keydown(function(e){
            if (e.which == sequence[expectedNextIndex])
            {
                expectedNextIndex++;
                if (expectedNextIndex >= sequence.length)
                {
                    callback();
                    expectedNextIndex = 0;
                }
            } else {
                expectedNextIndex = 0;
            }
        });
    };
})(jQuery);