Extension:Page Forms/Autocompleting on outside values

To have a field autocomplete on values from outside the wiki, take the following steps:

1. Create a page/web service that takes in a substring via the query string, and displays a set of autocompletion values; the values should be in JSON format, and look like the JSON returned by the MediaWiki API (see here for an example). This also makes it easy to autocomplete on the values from another wiki.

2. Decide on a short string to represent this URL.

3. Add a line to LocalSettings.php that looks like this: The URL in this line should look like a call to that web service, but with the substring replaced by the string " ".

4. Add the parameter "autocomplete from url=URL-identifier-string" to the relevant field in the form definition.