function showtab(n)
{
	for (var i=1; i<=10; i++)
	{
		var tab = document.getElementById("tab"+i);
		if (!tab)
			break;
		tab.className="inactive";
		var content = document.getElementById("tab_content"+i)
		if (content)
			content.style.display="none";
	}
	document.getElementById("tab"+n).className="active";
	document.getElementById("tab_content"+n).style.display="block";
	return false;
}