function ajaxRequest(){
    //alert("Ajax requested!");
 var activexmodes=["Msxml2.XMLHTTP", "Microsoft.XMLHTTP"] //activeX versions to check for in IE
 if (window.ActiveXObject){ //Test for support for ActiveXObject in IE first (as XMLHttpRequest in IE7 is broken)
  for (var i=0; i<activexmodes.length; i++){
   try{
    return new ActiveXObject(activexmodes[i])
   }
   catch(e){
    //suppress error
   }
  }
 }
 else if (window.XMLHttpRequest) // if Mozilla, Safari etc
  return new XMLHttpRequest()
 else
  return false
}

//Sample call:
//var myajaxrequest=new ajaxRequest();
var mypostrequest=new ajaxRequest();
function ajaxPost(){
    mypostrequest.onreadystatechange=function(){
        if((mypostrequest.readyState == 2)||(mypostrequest.readyState == 3)){
            document.getElementById('form_result').innerHTML = 'Sending request....';
            }
     if (mypostrequest.readyState==4){
      if (mypostrequest.status==200 || window.location.href.indexOf("http")==-1){
        //verifica se é erro ou não
        var verString = mypostrequest.responseText.substr(0,8);
        var resposta = mypostrequest.responseText.substr(13);
        if(verString == '&error=1'){
            //é erro, posta msg de erro
            document.getElementById("form_result").innerHTML = resposta;
        }else{
            //não é erro, posta username
            var userIndex = mypostrequest.responseText.lastIndexOf('=');
            var user = mypostrequest.responseText.substring(userIndex+1);
            document.getElementById("form_result").innerHTML = user + ' logged in.';
            window.location.reload();
        }
      }
      else{
        document.getElementById("form_result").innerHTML= "Error. Please try again."
       //alert("An error has occured making the request. "+ mypostrequest.responseText)
      }
     }
    }
    var loginvalue=encodeURIComponent(document.getElementById("port_login").value);
    var pwdvalue=encodeURIComponent(document.getElementById("port_pwd").value);
    var langvalue=encodeURIComponent(document.getElementById("port_lang").value);
    var parameters="login="+loginvalue+"&pwd="+pwdvalue+"&lingua="+langvalue; 
    mypostrequest.open("POST", "http://www.fiveblackcats.com/wpdir/wp-includes/php/trata_login.php", true)
    mypostrequest.setRequestHeader("Content-type", "application/x-www-form-urlencoded")
    mypostrequest.send(parameters)
}