function correctCityBox()
{
	var regionId = $('select#selectRegion').val();
	$.getJSON('ajax/get_citylist.php', { regionId : regionId }, function(data) { recreateCitySelect(data); });
}

function recreateCitySelect(options)
{
	document.getElementById('selectCity').options.length = 0;
	$('select#selectCity').addOption('0', 'alle Städte');
	$('select#selectCity').addOption(options);
	document.getElementById('selectCity').selectedIndex = 0;
}