(function ($) {
    $.fn.Middle = function () {
        return this.each(function (i) {            
            this.onload = function () {
                var h = $(this).height();
                var oh = $(this).outerHeight();
                var mt = (h + (oh - h)) / 2;
                $(this).css("margin-top", "-" + mt + "px");
                $(this).css("top", "50%");
                $(this).css("position", "absolute");

                var w = $(this).width();
                var ow = $(this).outerWidth();
                var ml = (w + (ow - w)) / 2;
                $(this).css("margin-left", "-" + ml + "px");
                $(this).css("left", "50%");
                $(this).css("position", "absolute");
            }
        });
    };
})(jQuery);