I've made a basic Joomla module for my site as a shoutbox. But I'd like to put AJAX in it (I know a similar module with AJAX already exists on JED but this more a project for me to learn how AJAX works in a Joomla module).
The usual AJAX stuff where you redirect to a new php file obviously doesn't work as the file will not be defined as
defined('_JEXEC') or die('Restricted access');
will fail in a new page. And defining _JEXEC to be equal to one (as I've read in several posts on SO) as far as I've read on Joomla Docs is a security risk as it provides an entry point onto the site.
The way the other shoutbox module I've seen does is to point back at a function in the helper.php file. Which makes sense to me as that is where all the functions should normally be stored. However I'm unclear as to how to the module was accessing the helper.php file on a onSubmit() (or a related) command and was hoping someone could shed some light on this.
I don't actually need anything specific to my shoutbox module - this is more a question of how to get AJAX functionality in Joomla modules and how it is arranged