function toggleContactMethod(b)
{
    if (!(b = document.getElementById('contactMethodCheckbox')) ||
        !(e = document.getElementById('contactMethod')) ||
        !(f = document.getElementById('contactMethodEmail')) ||
        !(g = document.getElementById('contactMethodPost')))
    {
        return;
    }

    if (!b.checked)
    {
        e.style['opacity'] = '0.5';
        e.style['filter'] = 'alpha(opacity=50)';
        f.checked = false;
        f.disabled = true;
        g.checked = false;
        g.disabled = true;
    }
    else
    {
        e.style['opacity'] = '1.0';
        e.style['filter'] = 'alpha(opacity=100)';
        f.checked = true;
        f.disabled = false;
        g.checked = false;
        g.disabled = false;
    }
}