function changeStyle(id) {
	bara = document.getElementById(id);
	if (bara.className == 'main_menu_selected') {
		return false;
	}
	if (bara.className == 'main_menu') {
		bara.className = 'main_menu_over';
	}
}

function returnStyle(id) {
	bara = document.getElementById(id);
	if (bara.className == 'main_menu_selected') {
		return false;
	} else {
		bara.className = 'main_menu';
	}
}

function createTabs() {
	thisOne = document.getElementById("tabs");
	items = thisOne.getElementsByTagName("div");
	var tabs = Math.round(items.length / 3);
	for (i = tabs; i > 0; --i) {
		var tabId = 'tab-' + i;
		var tab = document.getElementById(tabId);
		tab.className = 'tab';
		tab.style.zIndex = tabs - i;
		if (tabId != 'tab-1') { 
			tab.style.marginLeft = '-7px';
		}
		document.getElementById('menu-' + i).style.visibility = 'hidden';
	}
}

function selectTab(tabId) {
	createTabs();
	var tab = document.getElementById("tab-" + tabId);
	tab.className = 'tabSelected';
	tab.style.zIndex = '10';
	document.getElementById('menu-' + tabId).style.visibility = 'visible';
}