var opentab = "1";
function showtab() {
	var tab = arguments[0];
	var tabs = document.getElementById("tabs").getElementsByTagName("li");
	if (opentab != tab) {
		document.getElementById("tab" + opentab).style.display = "none";
		tabs[opentab-1].className = "";
		document.getElementById("tab" + tab).style.display = "block";
		tabs[tab-1].className = "current";
		opentab = tab;
	}
	tab = tabs = null;
}