function getElementById(id) {
	return document.getElementById(id);
}
function changeClass(id, className) {
	var obj;
	if (obj = getElementById(id)) {
		obj.className = className;
	}
}
function toggleVisibility(id) {
	var obj;
	if (obj = getElementById(id)) {
		if (obj.style.display == 'block') {
			obj.style.display = 'none';
		} else {
			obj.style.display = 'block';
		}
	}
}