function main_open(id,fon) {
  document.getElementById(id).style.display = 'block';
  document.getElementById(fon).className = 'active';
}
function main_close(id,fon) {
  document.getElementById('main0').style.display = 'none';
  document.getElementById(id).style.display = 'none';
  document.getElementById(fon).className = 'passive';
}

function change_main(id) {
	for (i = 1; i <= 4; i++) {
		maindiv =  'main'+i;
		fon = 'fon'+i; //alert(maindiv+'|'+fon+'/');
		document.getElementById('main0').style.display = 'none';
		if (i != id) {
			document.getElementById(maindiv).style.display = 'none';
			document.getElementById(fon).className = 'passive';
		}
		else {
			document.getElementById(maindiv).style.display = 'block';
			document.getElementById(fon).className = 'active';
		}
	}
}