var xmlHttp = getXmlHttpObject();

function loadList(tb,id)
 {
  xmlHttp.open('GET', 'req.php?table='+tb+'&id='+id, true);
  xmlHttp.onreadystatechange = stateChanged;
  xmlHttp.send(null);
 }
	
function addOption(select, value, text) 
 {
  var option = document.createElement("option");
  option.value = value,
  option.text = text;
  try 
   {
    select.add(option, null);
   } 
  catch(e) 
   {
    select.add(option);
   }
 }

function getSelected(select) 
 {
  return select.options[select.selectedIndex].value;
 }

function stateChanged() 
 {
  if(xmlHttp.readyState == 4) 
   {
    if (xmlHttp.status == 200) 
     {
      var resp = xmlHttp.responseText;
      
      if(resp) 
       {
	       var values = resp.split(';');
	       var listId = values.shift();
	       var select = document.getElementById(listId);
	       while (select.options.length) 
	        {
	         select.remove(0);
	        } 
	       if(listId == 'sped') 
	        {
	         addOption (select, 0, 'Selezionare tipo spedizione');
	        }
	       var limit = values.length;
	       for(i=0; i < limit; i++) 
	        {
	         var pair = values[i].split('|');
	         addOption(select, pair[0], pair[1]);
	        }
	      }
     } 
    else 
     {
      alert(xmlHttp.responseText);
     }
  }
 }

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