navigation = function() {
	if (!document.getElementsByTagName) return false;
	if (!document.getElementById) return false;
	var url = document.location.toString();
	var nav = url.split('show_nav=');
	var body = document.getElementsByTagName('body')[0];
	var id = body.id;
	if (id == 'Index') {
		document.getElementById('nav1').className = 'nav_on';
	} else {
		if (!document.getElementById('navigation')) return false;
		if (!nav[1]) return false;
		var div = document.getElementById('navigation');
		var links = div.getElementsByTagName('a');
		for (var i=0; i<links.length; i++ ) {
			if (links[i].id == 'nav'+nav[1].charAt(0)) {
				links[i].className = 'nav_on';
			} else {
				links[i].className = 'nav_off';
			}
		}
	}
}

add_load_event(navigation);