function show_div_hid(id) {
	if (document.getElementById(id) != null) {
		if (document.getElementById(id).style.display == "none") {
			document.getElementById(id).style.display = 'block';
		} else {
			document.getElementById(id).style.display = 'none';
		}
	}
}
function hide_div(id) {
	if (document.getElementById(id) != null) {
		document.getElementById(id).style.display = 'none';
	}
}
function show_div(id) {
	if (document.getElementById(id) != null) {
		document.getElementById(id).style.display = 'block';       
	}
}
function changeClass(id, class_name) {
	document.getElementById(id).className = class_name;
}