How to run custom JavaScript immediately before form is submitted

Created by Phil Kurth, Modified on Fri, 1 Jul, 2022 at 9:59 AM by Phil Kurth

Submission steps provide a way to intercept a form submission and run custom JavaScript immediately before. This is useful if you perhaps want to fire tracking events or implement something that requires some JavaScript-based handling before the payload is sent to the server.

acf.addAction( "af/form/setup", function( form ) {
    af.addSubmissionStep( form, 10, function( callback ) {
        
        // Add your custom JS code here...

        // Invoke the callback to allow the next submission step to fire. If this is not called, the form won't submit and any submission handlers with a later priority won't be invoked. 
        callback();
    });
});