function updateDep() {
	var arr = new Date( document.getElementById('arr_y').value, parseInt(document.getElementById('arr_m').value) - 1, document.getElementById('arr_d').value );
	var dep = new Date( document.getElementById('arr_y').value, parseInt(document.getElementById('arr_m').value) - 1, parseInt(document.getElementById('arr_d').value) + 1 );

	document.getElementById('arr_y').value = arr.getYear();
	document.getElementById('arr_m').value = arr.getMonth() + 1,
	document.getElementById('arr_d').value = arr.getDate();

	document.getElementById('dep_y').value = dep.getYear();
	document.getElementById('dep_m').value = dep.getMonth() + 1,
	document.getElementById('dep_d').value = dep.getDate();
}

function submitNB() {
	url = 'https://secure.netbooking.cz/arthotel/index.html?arrival='
		+ document.getElementById('arr_d').value + '.'
		+ document.getElementById('arr_m').value + '.'
		+ document.getElementById('arr_y').value
		+ '&departure='
		+ document.getElementById('dep_d').value + '.'
		+ document.getElementById('dep_m').value + '.'
		+ document.getElementById('dep_y').value;
	window.open(url, '', ',width=830,height=740,scrollbars=1,status=1,resizable=1,left=25,right=25');
	//alert( url );
}