function clk(a,id) {
		if (document.images) {
	 		(new Image()).src = 'http://www.opentravel.cz/clanky/link.html?c=' + id + '&href=' + escape(a.href);
  		}
	}

	function ref(img) {
		var i = document.getElementById('ref_img')
		i.src = '/img/reference/' + img + '.gif';
	}