function login(person_id)
{
	var email = $('email').value.trim();
	var password = $('password').value.trim();
	var stay_logged_in = $('stay_logged_in').checked;
	
	var params = "action=";
	
	if (!person_id)
	{
		if (email == '' || password == '')
		{
			alert('Please enter an email and password.');
			return;
		}

		if (!isValidEmail(email))
		{
			alert('That does not appear to be a valid email.');
			return;
		}

		params += "check_login&email=" + email + "&password=" + password;
	}
	else
	{
		params += "login&person_id=" + person_id + "&stay_logged_in=" + stay_logged_in;
	}

	new Ajax.Request('login.php', {
		method: 'get',
		parameters: params,
		onFailure: function(){ alert('Login failed.') },
		onException: function(o,e) { alert(e) }
	});
}