Inserting Javascript into admin footer wordpress

Question

I need to add Livechat widget on all WordPress admin pages (backend).

The Livechat JavaScript code is this:

<!-- Start of LiveChat (www.livechatinc.com) code -->
<script type="text/javascript">
window.__lc = window.__lc || {};
window.__lc.license = 12345678;
(function() {
  var lc = document.createElement('script'); lc.type = 'text/javascript'; lc.async = true;
  lc.src = ('https:' == document.location.protocol ? 'https://' : 'http://') + 'cdn.livechatinc.com/tracking.js';
  var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(lc, s);
})();
</script>
<noscript>
<a href="https://www.livechatinc.com/chat-with/10437202/" rel="nofollow">Chat with us</a>,
powered by <a href="https://www.livechatinc.com/?welcome" rel="noopener nofollow" target="_blank">LiveChat</a>
</noscript>
<!-- End of LiveChat code -->

Livechat has a plugin for the chat to work on the front-end pages. I actually wanted to add this code to every page of WordPress back-end.

I was thinking of putting it in the admin footer through the functions.php of my child theme, but I'm not sure how to put this code together.

The code I am inserting into the child theme is this:

function remove_footer_admin () {
    echo 'My footer text. Thank you WordPress for giving me this filter.';
}
add_filter( 'admin_footer_text', 'remove_footer_admin' );

Where should I put this code to work?

Answer 1

You can add JavaScript code in admin footer using admin_footer hook.

If you also need to add same code on the front-end, then apply wp_footer hook too.

Here is a complete code goes in child theme's functions.php:

// Function to render LiveChat JS code
function lh_add_livechat_js_code() {
?>
    <!-- Start of LiveChat (www.livechatinc.com) code -->
    <script type="text/javascript">
    window.__lc = window.__lc || {};
    window.__lc.license = YOUR_KEY; // use your license key here
    (function() {
      var lc = document.createElement('script'); lc.type = 'text/javascript'; lc.async = true;
      lc.src = ('https:' == document.location.protocol ? 'https://' : 'http://') + 'cdn.livechatinc.com/tracking.js';
      var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(lc, s);
    })();
    </script>
    <noscript>
    <a href="https://www.livechatinc.com/chat-with/10437202/" rel="nofollow">Chat with us</a>,
    powered by <a href="https://www.livechatinc.com/?welcome" rel="noopener nofollow" target="_blank">LiveChat</a>
    </noscript>
    <!-- End of LiveChat code -->
<?php
}
add_action( 'admin_footer', 'lh_add_livechat_js_code' ); // For back-end
add_action( 'wp_footer', 'lh_add_livechat_js_code' ); // For front-end