After upgrading WordPress from 4.9.13 to 5.3.2 some scripts on website stop working in weird way... (example for clndr.js).

All scripts are added via wp_register_script and wp_add_inline_script WordPress' functions.

At bottom of <body> there are three scripts as always:

<script type='text/javascript' src='http://example.com/clndr.min.js'></script>
<script type='text/javascript' src='http://example.com/calendar.js'></script>
<script type='text/javascript'>
    var calendar = create_calendar();

Relevant part of calendar.js

function create_calendar()
    var calendar = $('#Calendar').clndr({
        // clndr options

    return calendar;

All scripts should run in right order, but they are not working and in browser console I have this error: TypeError: $(...).clndr is not a function

Also, changing call to create_calendar in this way:

window.addEventListener("load", function(){
    var calendar = create_calendar();

changes only order of errors in console.

If I understand everything correctly, this should just work.. Any ideas? Or hints how to debug this?


According to @fuxia comment:

Solution is removing jQuery included by WordPress just before register/enqueue custom jQuery (see https://stackoverflow.com/a/27048128).

So if you include some jQuery on your own, then add


just before register/enqueue custom jQuery script in wp_enqueue_scripts action.

Or if you want jQuery included by WordPress just remember, that it's in no-conflict mode and $ is undefined. See https://wordpress.stackexchange.com/a/2896/182809 for more details.

| improve this answer | |
  • -1 for what exacly? – acinis Feb 17 at 17:57

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