function switchtab(n) {
for(i=1; i<4; i++) {
	document.getElementById('zakl' + i).className = 'dzaklu';
	document.getElementById('fs' + i).style.display = 'none';
}	
	document.getElementById('zakl' + n).className = 'dzakl';	
	document.getElementById('fs' + n).style.display = 'block';
}