function zobrazHlavni() {
	document.getElementById('jedna').style.visibility='hidden';
	document.getElementById('dva').style.visibility='hidden';
	document.getElementById('tri').style.visibility='hidden';
	document.getElementById('ctyri').style.visibility='hidden';
	
	document.getElementById('nula').style.visibility='visible';
}

function zobraz(id) {
	document.getElementById('nula').style.visibility='hidden';
	document.getElementById('jedna').style.visibility='hidden';
	document.getElementById('dva').style.visibility='hidden';
	document.getElementById('tri').style.visibility='hidden';
	document.getElementById('ctyri').style.visibility='hidden';
	
	document.getElementById(id).style.visibility='visible';
}