Display a function using AJAX

You’re not hooking the function to wp_ajax correctly. You need to replace the my_action part with your action name that you’re using the in AJAX request. In your case it’s display_user_table. You also need to hook it on to wp_ajax_nopriv so that it works for logged out users. Here’s your hook with those changes:

add_action('wp_ajax_diplay_user_table', 'diplay_user_table');
add_action('wp_ajax_nopriv_diplay_user_table', 'diplay_user_table');
function diplay_user_table() {
    echo "function is loading in div";
    wp_die();
}