function createObject() {
  var request_type;
  var browser = navigator.appName;
  if (browser == "Microsoft Internet Explorer") {
    request_type = new ActiveXObject("Microsoft.XMLHTTP");
  } else {
    request_type = new XMLHttpRequest();
  }
  return request_type;
}

var http = createObject();
var nocache = 0;

function login() {
  document.getElementById('login_response').innerHTML = "Loading..."
  var email = encodeURI(document.getElementById('emailLogin').value);
  var psw   = encodeURI(document.getElementById('pswLogin').value);
  nocache = Math.random();
  http.open('get', 'login.php?action=login&email='+email+'&psw='+psw+'&nocache = '+nocache);
  http.onreadystatechange = loginReply;
  http.send(null);
}

function loginReply() {
  if  (http.readyState == 4) {
    var response = http.responseText;
    if (response == 0) {
      document.getElementById('login_response').innerHTML = 'Login failed! Verify user and password';
    } else {
      document.getElementById('login_form').style.display = "none";
      document.getElementById('login_response').innerHTML = response + '<br><a href="logout.php" style="color:red">Logout</a>';
    }
  }
}