jQuery(document).bind('ajaxComplete', function(e, xhr, options){ 
  if(xhr.getResponseHeader('Content-Type').indexOf('text/javascript')!== -1){
    eval(xhr.responseText);
  }
});

var $D = {

  Post: function(form){
    var f = jQuery(form);
    jQuery.post(f.attr('action'), f.serialize());
  },
  
  Update: function(expression, url, data) {
    jQuery.post(url, data, function(responseText, status) {
      jQuery(expression).html(responseText);
    });
  }

}