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

function login(form)
{
	var username = document.getElementById('username').value;
    var password = document.getElementById('password').value;
    var http = getHTTPObject();
    var url = form.action;
    
    http.open('get', url, false, username, password);
    http.send('');
    if (http.status == 200) 
    {
		document.location.href = form.action;
	} 
	else 
	{
        alert('Incorrect username and/or password!');
    }
    return false;
}

function logout(form)
{
	var http = getHTTPObject();
    http.open('get', form.action, false, 'null', 'null');
    http.send('');
    alert('You have been logged out.');
    return false;
}