jQuery plugin for centering vertically and/or horizontally

jquery.center.js

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

Usage:

$('#myelement').vcenter();