function chama(uf){
    document.getElementById('listacidades').innerHTML = " Aguarde, carregando... ";
    ajaxCidades(uf);
}
function ajaxCidades(uf){
req = null;
// Procura por um objeto nativo (Mozilla)
if (window.XMLHttpRequest) {
req = new XMLHttpRequest();
req.onreadystatechange = processReqChange;
req.open("GET","listCidades.php?uf="+uf,true);
req.send(null);
// Procura por uma versão ActiveX (IE)
} else if (window.ActiveXObject) {
req = new ActiveXObject("Microsoft.XMLHTTP");
if (req) {
req.onreadystatechange = processReqChange;
req.open("GET","listCidades.php?uf="+uf,true);
req.send();
}
} else {


function getHTTPObject() {
var req;

try {
 if (window.XMLHttpRequest) {
  req = new XMLHttpRequest();

  if (req.readyState == null) {
   req.readyState = 1;
   req.addEventListener("load", function () {
   req.readyState = 4;

   if (typeof req.onReadyStateChange == "function")
    req.onReadyStateChange();
   }, false);
  }

  return req;
 }

 if (window.ActiveXObject) {
  var prefixes = ["MSXML2", "Microsoft", "MSXML", "MSXML3"];

  for (var i = 0; i < prefixes.length; i++) {
   try {
    req = new ActiveXObject(prefixes[i] + ".XmlHttp");
    return req;
   } catch (ex) {};
  }
 }
} catch (ex) {}

alert("XmlHttp Objects not supported by client browser");
}

req.onreadystatechange = processReqChange;
req.open("GET","listCidades.php?uf="+uf,true);
req.send();

}
}

function processReqChange(){
if (req.readyState == 4) {
if (req.status ==200) {
if(req.responseText==""){
document.getElementById('listacidades').innerHTML = "<font color=\"#ff0000\"><i><b>&nbsp; &nbsp;&nbsp; - Nenhuma informação cadastrada</b></i></font>";
} else {
document.getElementById('listacidades').innerHTML = req.responseText;
}
} else {
alert("Houve um problema ao obter os dados:\n" + req.statusText);
}
}
}