$.expr[':'].containsCaseInsensitive = function (n, i, m) {
return jQuery(n).text().toUpperCase().indexOf(m[3].toUpperCase()) >= 0;
};
.expr is not recognized.
To ensure it's defined, I included a CDN link below:
<script src="https://cdnjs.cloudflare.com/ajax/libs/sizzle/2.2.1/sizzle.js"></script>
If the script is in the header, expr should be defined. But sometimes errors may occur like:
Uncaught TypeError: Cannot read properties of undefined (reading 'expr')