function switchHighlight(tab){
	try{
		i=0;
		var el = document.getElementById('historical_'+i);
		while(typeof(el) != 'undefined'){
			el.className = "";
			i++;
			el = document.getElementById('historical_'+i);
		}
	}catch(ignore){}
	document.getElementById('historical_'+tab).className = "act";

	try{
		i=0;
		var el = document.getElementById('container_'+i);
		while(typeof(el) != 'undefined'){
			el.style.display = "none";
			i++;
			el = document.getElementById('container_'+i);
		}

	}catch(ignore){}
	document.getElementById('container_'+tab).style.display = "block";
	return true;
}