user = document.getElementById("user").value;
    password = document.getElementById("password").value;

     var data = JSON.stringify({"nick": user,"pass": password});




    var xhr = new XMLHttpRequest();

    xhr.open("POST","http://twserver.alunos.dcc.fc.up.pt:8008/register", true);
    //xhr.setRequestHeader("Content-Type","text/plain");

 xhr.send(data);


     xhr.onreadystatechange = function()
     {
    alert("readystatechange");


     if(xhr.readyState==4)
         {
        alert("yesss");
        var response = JSON.parse(xhr.responseText);
         if(response.error == null)
         {
                    alert("Foi aceite");
             aux();
                 }
         else alert("Password errada");
         }
     }