function controlla() {
	var pagCurrent;
	var npag;
	pagCurrent  = document.getElementById('pag').value;
	npag		= document.getElementById('npag').value;
	if (npag != 0) {
		if  (pagCurrent == document.getElementById('npag').value)
			document.getElementById('avanti').style.visibility = 'hidden';
		if 	( pagCurrent < document.getElementById('npag').value )
			document.getElementById('avanti').style.visibility = 'visible';
		if 	( pagCurrent == 1 )
			document.getElementById('indietro').style.visibility = 'hidden';
		document.getElementById('div1').style.visibility = 'visible';		
	}
}
function avanti() {
	pagCurrent = document.getElementById('pag').value;
	document.getElementById('div'+pagCurrent).style.visibility = 'hidden';
	pagCurrent++;
	document.getElementById('div'+pagCurrent).style.visibility = 'visible';
	document.getElementById('pag').value = pagCurrent;
	document.getElementById('indietro').style.visibility = 'visible';
	if 	( pagCurrent == document.getElementById('npag').value )
		document.getElementById('avanti').style.visibility = 'hidden';
}
function indietro() {
	pagCurrent = document.getElementById('pag').value;
	document.getElementById('div'+pagCurrent).style.visibility = 'hidden';
	pagCurrent--;
	document.getElementById('div'+pagCurrent).style.visibility = 'visible';
	document.getElementById('pag').value = pagCurrent;	
	document.getElementById('avanti').style.visibility = 'visible';
	if 	( pagCurrent == 1 )
		document.getElementById('indietro').style.visibility = 'hidden';
}
window.onload = controlla;