Updated : how to make email optional while user registration using default wordpress form

I wonder if there is any way to make email an optional field while registering using default form. So that those who don't know mail may leave it blank.

I got code from stackexchange but that doesn't seems to work.I added code to functions.php under theme folder.

add_action('user_profile_update_errors', 'my_user_profile_update_errors', 10, 3);
function my_user_profile_update_errors($errors, $update, $user) {
    $errors-remove('empty_email');
}

add_action('user_new_form', 'my_user_new_form', 10, 1);
add_action('show_user_profile', 'my_user_new_form', 10, 1);
add_action('edit_user_profile', 'my_user_new_form', 10, 1);
function my_user_new_form($form_type) {
    ?
    script type=text/javascript
    jQuery('#email').closest('tr').removeClass('form-required').find('.description').remove();

    ?php if (isset($form_type)  $form_type === 'add-new-user') : ?
        jQuery ('#send_user_notification') .removeAttr('checked');
    ?php endif; ?
    /script
    ?php
}

UPDATE

I mend to have optional mail registration on default registration page of wordpress (http://example.org/wp-login.php?action=register) not in dashboard.

Sorry for clarity in question .Won't repeat it again( am a newbie )

Any help is much appreciated. Thanks

Reference