This is how to do true AJAX...

Yep, real AJAX works. All that's left for me to upload my changes is to fix a CCK-related issue.

But it looks like this post didn't garner any interest.

Oh, well.

I did figure out dynamic AJAX default options for targets (and sources) as well. I imagine you don't have problems setting up the default for the source field. For targets, you need to send your activeselect function the correct value via the 'extra' parameter and then make the corresponding entry in your dropdown list the 'selected' one. Only set the first entry as 'selected' if there is no 'extra' value.

Things to watch out for

- if you have a dropdown list of key->value pairs where key!=value, then make sure the value you pass via 'extra' is checked correctly so that 'selected' is set correctly. In my case, I have state abbreviations->state names and was sending (or checking) the wrong one so the for the longest time I wasn't getting the default set correctly. I was either sending the key and checking the value or the other way around.

- at least as a cck module goes, you have to make sure that the value you send to 'extra' is the current value. For example, if you are creating a new content type, there are no initial values for any fields, which is what you'd expect. On preview, both $_POST and $items contain the submitted value and either will do (if I recall correctly). If you're setting 'extra' from either of these, the default value of the target should be okay and reflect the choice you made. You can then submit and the correct values are saved. If you then edit an existing node, $_POST won't have values, but $item will. If you then preview after changing a value, $_POST will have the correct value (the new one) and $items will have the stored value. So you need to grab $_POST in this case. In other words, use an if/else or ?: to make sure the most recent value takes precedence over the stored value and is sent to activeselect via 'extra'. I hope that all makes sense. The same goes for the source, come to think of it. The only difference is that you just put it into #default_value, not 'extra'.

- for some reason, I didn't consistently get a result for 'extra' if I drupal_set_message'd it out, even though it otherwise behaved correctly, so make sure that what you're GOING TO SEND is correct and trust that the function receives the right value(s).

By 'extra' in all of my references above, I may mean 'activeselect_extra' or whatever it's called in the form definition. It's called 'extra' inside your activeselect function.

This will all be in my cck_address module if some cck people can tell me how my newly added column will be propagated to existing instances. That's the only thing hanging me up right now.

API.txt says that it must be a string and not an array. So in my case, I'm passing it a two character state code (or was it the full state name?). Either way, in my activeselect function, I then lookup the allowed values for the state by using the country (which was passed in via 'string'). These will be passed via AJAX as the #options. I modified the loop in the example from API.txt so that the first element is set to 'selected' only if 'extra' is not set. Otherwise, if $key == $extra, set that one to 'selected'. Does that make sense?

I did get a tip on how to fix my cck issues on my module, so expect to see the update sometime next week.

I just followed the basic outline of API.txt from activeselect and it mentions modifying the your_module_activeselect function to output what you need. It sounds like you figured that out.

As for my cck_address module: I have just added Canadian support and made it simple (I think) to add other countries data. I use Wednesdays as my module update day, so you should see the update posted then. I had hoped that the cck issue I am having would have had a simple solution where I could simply call an existing cck function to take care of it; but it looks like I'll have to write my own function instead. Oh well.

Anyway, I'm glad I could help.

BTW, are you working on a module that you'll release to the community?

Just uploaded the new release of cck_address yesterday. Find it here: http://drupal.org/project/cck_address. The activeselect stuff should be easy to see, but of course, if you have questions, let me know. I'll be happy to explain anything.