Drupal tightens up node_load()
The other day we had an error on our Drupal 7 site where users would receive error messages whenever they tried to register for a conference. The site would register them, but the only thing the user would see is a JavaScript dialog box with an AJAX callback error message with some code in it; since the users didn't know that the site had registered them, they kept clicking the register button, getting registered multiple times. Not a desirable state of affairs.
Loading Form Definition Include Files in Drupal 7
This post was written 06/12/2015 and was migrated over from my Drupal 7 site, which is now offline. Because of that, certain demonstrations in this post may not be functional.
Recently I had to include a form within an existing set of nodes (using hook_node_view), and this form had to make an AJAX callback. I put the form definition and Ajax callback function in a separate file for convenience. From my_ajax_test.module: