Event.observe(window, 'load', ad_300x250, false);
function ad_300x250(){
  var url    = '/fra_ad_300x250.php';
	var pars   = '';
	var target = 'div-ad_300x250';
	var myAjax = new Ajax.Updater(target, url, {	method: 'get',	parameters: pars});
}