jQuery center extension

jquery.center.js

$.fn.extend({
        center: function() {
            this.css("position", "absolute");
            this.css("top", Math.max(0, (($(window).height() - $(this).outerHeight()) / 2) +
                $(window).scrollTop()) + "px");
            this.css("left", Math.max(0, (($(window).width() - $(this).outerWidth()) / 2) +
                $(window).scrollLeft()) + "px");
            return this;
        }
    });