function toggle_display(obj) {
	if ((!document.getElementById) && document.all) {
		document.getElementById = function(id) { return document.all[id]; };
	}
	var el = document.getElementById(obj);
	if (el.style.display != 'none')
		el.style.display = 'none';
	else
		el.style.display = 'block';
}