jQuery.fn.center = function(target)
{
	var $target = $(target);
	
	var target_pos = $target.position();
	
    this.css("position","absolute");
    this.css("top", (($target.height() - this.outerHeight()) / 2) + target_pos.top + "px");
    this.css("left", (($target.width() - this.outerWidth()) / 2) + target_pos.left + "px");
    return this;
}