Ajax click function is not working in WordPress functions

I would appreciate some help. I am trying to create a save bookmark plugin through wordpress functions file (all code in one place). The problem is I am unable get the ajax, jquery to work I am not sure what part of it is not working. You click on link and it’ll call ajax and then php where it’ll save the post_id, user_id into the database.

Here’s the code (funtions.php):

echo '<a href="#bookmark" class="bookmark">Bookmark</a>';

add_action('admin_head', 'bookmark_add');

function bookmark_add() { ?>
<script type="text/javascript">
jQuery(document).ready(function($) {
    $(document).on('click', '.bookmark', function(){
    console.log('bookmark_save_TEST');
    var data = {
        'action': 'bookmark_save',
        'user_id': 1234,
        'post_id': 3049291
    };
    // since 2.8 ajaxurl is always defined in the admin header and points to admin-ajax.php
    jQuery.post(bookmark_save.ajax_url, data, function(response) {
        alert('Got this from the server: ' + response);
    });
});
</script> <?php
}

add_action( 'wp_ajax_bookmark_save', 'bookmark_save_callback' );

 function bookmark_save_callback() {
 global $wpdb;
 $user_id = intval( $_POST['user_id'] );
 $post_id = intval( $_POST['post_id'] );

 $post_id += 10;

 echo $post_id;
 
// once the code above works, will uncomment this to add into the database.
 //$sql = $wpdb->query("INSERT INTO {$wpdb->prefix}wp_bookmarks(`user_id`,`post_id`) VALUES (%s, %d)", $user_id, $post_id);

exit();
}

Can someone please tell me what is it that keeps going wrong?

Answer

if you are using in admin area then use “add_action(‘admin_footer’, ‘bookmark_add’);” for frontend “add_action(‘wp_footer’, ‘bookmark_add’); “

also check your action.

'action': 'bookmark_save_callback',

add_action( 'wp_ajax_bookmark_save_callback', 'bookmark_save_callback' );
add_action( 'wp_ajax_nopriv_bookmark_save_callback', 'bookmark_save_callback' );

you can check for more info https://codex.wordpress.org/AJAX_in_Plugins