function page(id1,id2,triangle){
	document.getElementById(id1).className = 'dark'; 
	document.getElementById(id1).style.fontWeight = 'bold';
	if (id2 > 0){
		document.getElementById(id2).className = 'dark'; 
		document.getElementById(id2).style.fontWeight = 'bold';
	}
	document.getElementById('triangle').style.marginTop = triangle+"px";
}