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';
                }
        }
}