function changeProvinceCities(url, value, ProvinceId, CityId, form, query_event, null_option_value)
{
	if (!use_enhanced_js){
		form = document.forms[form];
		form.elements['event'].value = query_event;
		form.submit();			
		return false;
	}
	ProvinceSelect = $(ProvinceId);
	CitySelect = $(CityId);
	
	ProvinceSelect.disabled = 1;
	CitySelect.disabled = 1;
	CitySelect.innerHTML = "";
	OPTION = document.createElement('OPTION');
	OPTION.innerHTML = 'Updating...' ;
	CitySelect.appendChild(OPTION);
	
	new Ajax.Request(url+value, {
		method: "get",
		onSuccess: function(t) {
			//alert(t.responseText);
			eval(t.responseText);
			//var ajax_cities_ids = ['12','13'];
			//var ajax_cities_names = ['12','13']
			CitySelect.innerHTML = "";
			OPTION = document.createElement('OPTION');
			OPTION.innerHTML = '[ '+null_option_value+' ]' ;
			CitySelect.appendChild(OPTION);
			for(var i=0; i < ajax_cities_ids.length; i++)
			{
				OPTION = document.createElement('OPTION');
				OPTION.value = ajax_cities_ids[i];
				OPTION.innerHTML = ajax_cities_names[i] ;
				CitySelect.appendChild(OPTION);
			}
			ProvinceSelect.disabled = 0;
			CitySelect.disabled = 0;
		},
		onFailure: function(t) {
			ProvinceSelect.disabled = 0;
		}
	})
}