var xmlHttp2 = getXmlHttpObject2();

function load_lista(select1,select2,val){

	//Recupero i dati da inviare 
	var mainSelection = document.getElementById(select1); 
	var selezionato=mainSelection.options[mainSelection.selectedIndex].value;
		subSelection = document.getElementById(select2); 
		
		//Svuoto la secondo SELECT 
		for (var i = subSelection.length - 1; i >= 0; i--) 
		subSelection.remove(i);
	
	if(selezionato==6)
	{
		subSelection = document.getElementById('id_subdirettivo'); 
	}

	if(selezionato=="")
	{	
		for (var i = subSelection.length - 1; i >= 0; i--)
		{
		  subSelection.remove(i); 
		}
	}
	else
	{
		//Svuoto la secondo SELECT 
		for (var i = subSelection.length - 1; i >= 0; i--) 
		subSelection.remove(i); 

		xmlHttp2.open('GET', 'lista_ajax.php?choice=' + selezionato + '&op=' + val, true);
		xmlHttp2.onreadystatechange = stateChangedx;
		xmlHttp2.send(null);
	}

}



function stateChangedx() {
	if(xmlHttp2.readyState == 4) {
		//Stato OK
		if (xmlHttp2.status == 200) {
			var resp = xmlHttp2.responseText;
			
			if(resp) {
				
				resp=resp.replace(/\s+$|^\s+/g,"");
				
				//Le coppie di valori nella striga di risposta sono separate da ;
				var values = resp.split(';');
								
				var select = subSelection;
				
				//Elimina i valori precedenti
				while (select.options.length) {
					select.remove(0);
				} 
				
				var limit = values.length-1;
				
				var option = document.createElement("option");
					option.value = '',
					option.text = 'Seleziona';
					try {
							select.add(option, null);
						} catch(e) {
							//Per Internet Explorer
							select.add(option);
						}	
				
				for(i=0; i < limit; i=i+2) {
					
					//aggiunge un elemento <option>
					var option = document.createElement("option");
					option.value = values[i],
					option.text = values[i+1];
					try {
							select.add(option, null);
						} catch(e) {
							//Per Internet Explorer
							select.add(option);
						}	
					
				}
			}
		} else {
			alert(xmlHttp2.responseText);
		}
	}
}



function getXmlHttpObject2()
{
  var xmlHttp2=null;
  try
    {
    // Firefox, Opera 8.0+, Safari
    xmlHttp2=new XMLHttpRequest();
    }
  catch (e)
    {
    // Internet Explorer
    try
      {
      xmlHttp2=new ActiveXObject("Msxml2.XMLHTTP");
      }
    catch (e)
      {
      xmlHttp2=new ActiveXObject("Microsoft.XMLHTTP");
      }
    }
  return xmlHttp2;
}