The error message often occurs when outdated commands are used that are no longer supported in current jQuery versions.
Solution: If possible, reprogram the code so that it is up to date. Otherwise, the jQuery Migrate plugin, which allows the use of older code, can help.
<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script> <script src="https://code.jquery.com/jquery-migrate-1.4.1.min.js"></script>