Wix Forms events are fired in your site's backend when certain events related to forms occur in your site's backend. You can write event handlers that react to these events. Event handler functions receive data that corresponds to the event that has occurred. Use event handlers to create custom responses to forms events.
Note: Backend events don't work when previewing your site.
To add a forms event handler, add an events.js file to the Backend section of your site if one does not already exist. All event handler functions for your site are defined in this file.
Event handler functions are defined using the following pattern:
For example, an event handler that handles form submission updates looks like this: