var WAIT = '<br /><br /><img src="img/waiting.gif" alt="" align="middle" height="80px" width="80px"/> Chargement...';

function loadLogin() {
    var user = document.getElementById('user').value;
    var pass = document.getElementById('pass').value;
    if(user == "" || pass == "") // If fields are empty
        alert("Vous devez compléter tous les sujets !");
    else {
        ajax = Ajax();
        ajax.open('POST', 'php/login.php', true);
        ajax.onreadystatechange = function() {
            if(ajax.readyState == 4)
                document.getElementById('login').innerHTML = ajax.responseText;
            else
                document.getElementById('login').innerHTML = WAIT;
        }
        ajax.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
        ajax.send("login="+user+"&password="+pass);
    }
}

function logout() {
    ajax = Ajax();
    ajax.open('GET', 'php/logout.php', true);
    ajax.onreadystatechange = function() {
        if(ajax.readyState == 4)
            document.getElementById('login').innerHTML = ajax.responseText;
        else
            document.getElementById('login').innerHTML = WAIT;
    }
    ajax.send(null);
}

function onKeyDown(e) {
    if(e.keyCode == 13) loadLogin();
}