Ajax - Requisicao Estudando

xmlhttp.readState
xmlhttp.open
xmlhttp.onreadstatechange
xmlhttp.send

Ajax-Requisicao-ChegaramDados(2)

-----   try  -----

ajax_callback=false
function _req(){
 if(xmlhttp.readState==4){
 ajax_Callback(xmlhttp:responsetext);
}
}
function req(url,callback,data) {
  if(typeof data=="undefined" {
            data=null
            var method="get"
      }{
            var method="post"
      }
  ajax_callback=callback
  xmlhttp.open(method,url,thrue)
  xmlhttp.onreadystatechange=_req
  xmlhttp.setRequesthead("Content-type","application/x-www.form-urlencoded")
  xmlhttp.send(data)
{)

Ajax-Requisicao-ChegaramDados(1)

-script>
function chegaramdados(texto){
  var t=document.getElementById("txt2");
  t.value=texto
   }
function teste(){
   var t=document.getElementById("txt");
   var q=escape(t.value);
   req("encod.php"),chegaramdados,"txt="+q)
   }