Calling a javascript function from a form item ajax callback?

Question

I am working on a project and I think I am stuck on this. I have a form that I want to add points to a map as users edit it.

Here's a rundown on how the form works:

The user chooses a number (1-10) for how many stops they'd like to make from a select list. The select list defaults to 1 and below it there is a select list that lists all of the points of interest they can choose from. If they change the first select to 2 the ajax callback updates the form and adds an additional select box of POIs. That's working great.

What I'd like to be able to do is add the POI to a map on the page whenever they select it (with driving directions between them). I have an ajax callback on the POI select list in order to do this but I am having trouble figuring out where to go from here.

I have the following in my POI callback (for testing) and it works, but I am having trouble figuring out what ajax_command_ function to use to call a js function to add the point to the map.

$commands = array();
$commands[] = ajax_command_alert("Here!");
return array('#type' => 'ajax', '#commands' => $commands);

Basically I just need to pass the latitude and longitude of the POI (which I am gathering in the callback) and send it to a js function to then update the map. My first thought was using drupal_add_js but I couldn't get it working and discovered later that it was not the right way to go.

Any thoughts?

Answer 1

PHP:

$commands[] = ajax_command_alert("Here!");
$commands[] = array(
  "command" => 'your_custom_command',
  "latitude" => "45.23",
  "longitude" => "23.25"
);

Javascript:

Drupal.ajax.prototype.commands.your_custom_command = function(ajax, response, status) {
  if( response.latitude != "" ) {
    // do something
  }
};