function apply_option_boxes(target_element_id,array)
{$$('#'+target_element_id+' option').invoke('remove');for(var i=0,options=array.length;i<options;i++)
{var entry=array[i];if(typeof entry=='undefined')continue;var option=new Element('option',{value:entry[1]});option.update(entry[0]);$(target_element_id).insert({bottom:option})
if(option.value=="LON")
option.setAttribute('selected','selected');}}
function get_available_departure_airports(destination)
{var keys=destination_departure_airports.get(destination)||0;var airport_codes=(keys.length)?keys:uk_departure_airports.keys();var available_airports=[];airport_codes.each(function(airport_code)
{var destination_name=uk_departure_airports.get(airport_code);var airport=[destination_name,airport_code];available_airports.push(airport);});available_airports.sort();return available_airports;}
function get_available_departure_airport_groups(destination)
{var keys=destination_departure_airports.get(destination)||0;var airport_codes=(keys.length)?keys:uk_departure_airports.keys();var available_airport_groups=[];airport_codes.each(function(airport_code)
{var group_codes=airports_groups.get(airport_code);group_codes.each(function(group_code)
{var group_info=airport_groups.get(group_code);var group_order=group_info[0];var group_name=group_info[1];var airport_group=[group_name,group_code];available_airport_groups[group_order]=airport_group;});});return available_airport_groups;}
function update_departure_airports(destination)
{var available_departure_airports=get_available_departure_airports(destination);var available_departure_airport_groups=get_available_departure_airport_groups(destination);apply_option_boxes('bf_regions',available_departure_airport_groups);apply_option_boxes('bf_airports',available_departure_airports);if(typeof bf_airport!='undefined'&&bf_airport)
{var options=$$('#bf_airport option[value="'+bf_airport+'"]');if(options.length)options[0].setAttribute("selected","selected");}}