function toggleForm(id) {
    var e = document.getElementById(id);
    var v = e.className.indexOf('hidden') < 0;
    var c1 = (v) ? 'visible' : 'hidden';
    var c2 = (v) ? 'hidden' : 'visible';
    e.className = e.className.replace(c1, c2);
    if (e.className.indexOf(c2) < 0)
	e.className = e.className + ' ' + c2;
}