function _getEl(elName) {
	return document.getElementById(elName);
}

function showTab(n) {
	ids = ['twitter_updates','service_timing'];
	m = (n+1)%2;
	_getEl(ids[n]).className="active";
	_getEl(ids[m]).className="inactive";
	_getEl(ids[n]+'_head').className="active";
	_getEl(ids[m]+'_head').className="inactive";
}