(function($){
  $.fn.center = function(o){
    var o = $.extend({
        position : 'absolute',
        resizeEvent : false
      },o),
      w = $(window),//$('body'),
      top = (w.height()-this.height())/2,
      left = (w.width()-this.width())/2,
      _this = this,
      ownFunc = arguments.callee

    switch(o.position){
      case 'fixed':break;
      default:
        top += w.scrollTop();
        left += w.scrollLeft();
        o.position = 'absolute';
        break;
    }

    if (w.height() < this.height()) {
      top = 0;
    }

    if (w.width() < this.width()) {
      left = 0;
    }

    this.css({
      "top"       : top<0?0:top,
      "left"      : left<0?0:left,
      'position'  : o.position
    });

    if (o.resizeEvent){
      $(window).resize(function(){
        var p = o;
        p.resizeEvent = false;
        ownFunc.apply(_this,[p]);
      })
    }

    return this;
  }
})(jQuery);