function addEventOnSelect() {
	 $('GUID_ExtraTipType').addEvent('change', function(ev) {
	        var ajax = new Request({
	                        url:'/posta-popis/', 
	                        method: 'get',
	                        data: {'GUID': this.value},
	                        onComplete: function(data) {
	                            // nastav obsah vracenych elementu
	                        	updateElements(JSON.decode(data));
	                        }
	                    }
	                ).send();
	    }); 
}

window.addEvent("domready", function() {
	 addEventOnSelect();       
});