function chk_form(f)
{
    // email
    if (f.email.value.length < 1) {
        alert('You must enter your email address');
        f.email.focus();
        return false
    }

    // password
    if (f.password.value.length < 1) {
        alert('You must enter your password');
        f.password.focus();
        return false
    }

    return true;
}