function getObj(id) {
	var obj = null;
	if (document.getElementById) obj = document.getElementById(id);
	else if (document.all) obj = document.all[id];
	else if (document.layers) obj = document.layers[id];
	return obj;
}
function is_object(mixed_var){
	if(mixed_var instanceof Array) return false;
	else return (mixed_var !== null) && (typeof( mixed_var ) == 'object');
}
function toggleDisplay(id1, id2) {
	var obj1 = getObj(id1);
	var obj2 = getObj(id2);
	if(obj1.style.display=='none') {
		obj1.style.display='';
		obj2.style.display='none';
	}
	else {
		obj1.style.display='none';
		obj2.style.display='';
	}
}
function toggleSingleDisplay(id) {
	var obj = getObj(id);
	if (!is_object(obj)) return false;
	obj.style.display = (obj.style.display == 'none') ? '' : 'none';
}