var canSwitch = false;
if (parseInt(navigator.appVersion) >= 5 || navigator.appVersion.indexOf["MSIE 5"] != -1) canSwitch = true;

function deleteMainPage() {
	main_page = document.getElementById('main_page');
	if (main_page) {
		main_page.innerHTML = '';
	}
	return true;
}

function switchOff(ID) {
	if (canSwitch) {
		var subitems = document.getElementById(ID);
		if (subitems && subitems.style) {
			subitems.style.display = 'none';
		}
		
		deleteMainPage();
	}
	return true;
}

function switchOnOff(ID) {
	if (canSwitch) {
		var subitems = document.getElementById(ID);

		var visible = (subitems.style.display != 'none');

		if (visible) {
			subitems.style.display = 'none';
		} else {
			switchAllOff();
			subitems.style.display = 'block';
		}
		
		deleteMainPage();
	}
	return true;
}

function giveFocus() {
	if (document.forms[0] && document.forms[0].elements[0].type != 'hidden') {
		document.forms[0].elements[0].focus();
	}
	return true;
}