reCaptacha for HTML Forms

functions.php

<?php

function fws_enqueue_recaptcha() {
  $sitekey = mysitekey';
	wp_enqueue_script( 'fws-recaptcha', '//www.google.com/recaptcha/api.js?render=' . $sitekey, null, null, true );

}
add_action( 'wp_enqueue_scripts', 'oceanwp_child_enqueue_parent_style' );


add_filter( 'hf_validate_form', function( $error_code, $form, $data ) {
	$valid_captcha = '';
	if (isset($_POST['recaptcha_response'])) {
		$recaptcha_response = sanitize_text_field($_POST['recaptcha_response']);
		$secret = 'mysecretkey';
		$request = wp_remote_get('https://www.google.com/recaptcha/api/siteverify?secret=' . $secret . '&response=' . $recaptcha_response);
		$request_body = wp_remote_retrieve_body( $request );
		$recaptcha = json_decode($request_body);
		//var_dump($recaptcha);
		if ($recaptcha->score < 0.5) {
			$valid_captcha = 'invalid_captcha';
		}
	} else {
		$valid_captcha = 'invalid_captcha';
	}
	return $error_code;
}, 10, 3 );

add_filter( 'hf_form_message_invalid_captcha', function( $message ) {
    return 'Sorry, your message isn\'t valid, pleease try again';
});

recaptcha.js

// this isn't working
jQuery(document).ready(function($) {
	$('#contactbutton').on('click', function (event) {  
      event.preventDefault();
			grecaptcha.ready(function () {
				grecaptcha.execute(ajax_object_acf.site_key, { action: 'contactform_action' }).then(function (token) { 
					// submit the form
				}); 
			});
	});
});