function writeLayer(layerID,txt){
	 			txt="<select name='centro_vacanze' id='centro_vacanze' >" + txt + "</select>";
	 			obj=returnObject(layerID);
	 			obj.innerHTML=txt;
	 			

      }
      
function returnObject(layerID){
		if(document.all){
			return document.all[layerID];
		}else {
			return document.getElementById(layerID);
		}
		return null;
	 		
}