af/form/before_submission

Action fired immediately before a form’s submission handlers run. Use it to inspect the submitted values and abort the submission by calling af_add_submission_error() — the form is re-rendered with the error and submission handlers (post creation, user creation, notifications) do not run.

add_action( 'af/form/before_submission', function ( $form, $fields, $args ) {
    // Block the submission based on a submitted value.
    if ( af_get_field( 'agreed_to_terms' ) !== '1' ) {
        af_add_submission_error( 'You must agree to the terms before continuing.' );
    }
}, 10, 3 );

The handler receives the $form array, the $fields array, and the $args array. The hook fires before af/form/submission and before any built-in submission handlers (post-editing, user-editing, notifications, integrations). Calling af_add_submission_error() is the supported way to halt submission flow — returning early without calling it has no effect.

Modifiers

• af/form/before_submission — Applies to all forms.
• af/form/before_submission/key=FORM_KEY — Applies to forms with a specific key.
• af/form/before_submission/id=FORM_ID — Applies to forms with a specific post ID.

See also

• How to prevent form submission based on submitted values
• af/form/submission — Runs after this hook, once submission has been accepted.