How to create custom form with google captcha using AJAX

functions

function custom_form_callback( $atts ) {
	?>
	<form id="form" method="POST" action="">
		<input type="text" name="name" class="name" placeholder="Full Name"  required="required">
		<div class="g-recaptcha" data-sitekey="my-google-site-key" data-callback="enableBtn"></div>
		<input id="submit" type="submit" name="submit" value="Submit" disabled="disabled">
	</form>
	<?php
}
add_shortcode( 'custom-form', 'custom_form_callback' );
add_action( 'wp_ajax_captcha_checker', 'captcha_checker' );
add_action( 'wp_ajax_nopriv_captcha_checker', 'captcha_checker' );
function captcha_checker(){
	$recaptchaToken = $_POST['recaptchaToken'];
	$secret 	= "yot-secret-key-here";
	$response 	= null;
	$reCaptcha 	= new ReCaptcha($secret);
	if ($recaptchaToken) {
	    $response = $reCaptcha->verifyResponse(
	        $_SERVER["REMOTE_ADDR"],
	        $recaptchaToken
	    );
	    if( $response->success ){
	    	$result = $response->success;
	    }
	}
	die();	
}
add_action('wp_footer', function(){
  ?>
  <script src='https://www.google.com/recaptcha/api.js'></script>
  <script>
    jQuery(document).ready(function($){
      $('#form').on('submit', function(e){
        e.preventDefault();
        var recaptchaToken = grecaptcha.getResponse();
            $.ajax({
                type:"POST",
                data:{
                    action 			: 'captcha_checker', 
                    recaptchaToken 	: recaptchaToken
                },
                url : nickelAjaxHandler.ajaxurl,
                beforeSend:function(){
                    //
                },
                success:function(data){
                   console.log(data)
                }
            });
      });
    });
  </script>
  <?php
});