JS Action to execute code when a choice is changed.

action-on-choice-change.js

// Requires wp.hooks
// Make sure to set 'wp-hooks' and 'jquery' as dependencies when loading this script.
if ( ! wp || ! wp.hooks ) return;

( function( $ ) {
  
	wp.hooks.addAction( 'PC.fe.choice.set_choice', 'Custom_domain', function( model, view ) {
    // Do something here.
    // view.$el will give you the jQuery object of the current choice.
	} );

} )( jQuery );