Forminator 1.15.10 - include iframe in thank you message

forminator-thank-you-iframe.php

<?php 
/**
*
* Includes specified iframe in inline thank you message;
* note that it's quite "rough" and disables some sanitization
*
* by Adam/Panos/WPMU DEV
*
* use as MU plugin
* 
* Tested with Forminato 1.15.10 only - no promises for other versions
*
* To configure, see comments in code
*
**/


add_filter(
	'forminator_custom_form_thankyou_message',
	function( $message, $submitted_data, $custom_form ) {
		
		$form_id = 13376;  // SET FORM ID HERE; iframe will be injected to this form thank you message only
		
		if ( $form_id == $custom_form->id ) {
		
		add_filter( 'wp_kses_allowed_html', '_formi_thankyoumsg_wp_kses_allowed_html', 99, 2 );

		$message .= '<iframe src="https://fr.wikipedia.org/wiki/Main_Page" width="640" height="480">'; // replace URL with your own
		
		
		}
		return $message;
	},
	10,
	3
);


function _formi_thankyoumsg_wp_kses_allowed_html( $tags, $context ) {
	remove_filter( 'wp_kses_allowed_html', '_formi_thankyoumsg_wp_kses_allowed_html' );

	if ( 'post' === $context ) {
		$tags['iframe'] = array(
			'src'             => true,
			'height'          => true,
			'width'           => true,
			'frameborder'     => true,
			'allowfullscreen' => true,
		);
	}

	return $tags;
}