Launch a custom CF7 thank you popup

launch_custom_cf7_thank_you_popup.php

/**
 * Add custom JavaScript for Popup Maker to the footer of your site.
 *
 * Reference https://contactform7.com/dom-events/
 */
function launch_custom_cf7_thank_you_popup() { ?>
	<script type="text/javascript">
						
    		document.addEventListener( 'wpcf7submit', function( event ) {
      			PUM.open(123); // Change 123 to your popup's ID.
    		}, false );
				
	</script><?php
}
add_action( 'wp_footer', 'launch_custom_cf7_thank_you_popup', 500 );
/** 
 * Add the code above to your child theme's functions.php file or 
 * use a code snippets plugin.
 */