(function($) {
    $.fn.documentSize = function() {
        var dimensions = { width: 0, height: 0 };
        if (document.documentElement) {
            dimensions.width = document.documentElement.offsetWidth;
            dimensions.height = document.documentElement.offsetHeight;
        } else if (window.innerWidth && window.innerHeight) {
            dimensions.width = window.innerWidth;
            dimensions.height = window.innerHeight;
        }
        
        return dimensions;
    }
})(jQuery);