Wordpress Ajax returning full html of same page

Am trying to run Ajax call in my Woocommerce checkout page, but am always getting the full html of same page return.

add_action( 'wp_enqueue_scripts', 'theme_scripts' );
function theme_scripts() {
    wp_enqueue_script( 'theme_scripts', get_stylesheet_directory_uri() . '/assets/js/theme.js', array(), '1.0.0', true );
    wp_localize_script( 'theme_scripts', 'my_ajax_object', array( 'ajax_url' => admin_url( 'admin-ajax.php' ) ) );  
}

Am calling the ajax when address is changed

add_action('wp_footer','my_custom_ajax');
function my_custom_ajax(){
?>
<script>
        (function($){
   $( document.body ).on( 'updated_checkout', function(){
        $.ajax({
                url: my_ajax_object.ajaxurl,
                data: {
                    'action':'example_ajax_request',
                },
                success:function(data) {
                    console.log(data);
                },
                error: function(errorThrown){
                    console.log(errorThrown);
                }
            }); 
    });
})(jQuery); 
</script>
<?php
}

The example Function

  function example_ajax_request() {
echo 'ok';
         wp_send_json_success( 'It works' );
die();
    }

add_action( 'wp_ajax_example_ajax_request', 'example_ajax_request' );
add_action( 'wp_ajax_nopriv_example_ajax_request', 'example_ajax_request' );