How to resolve "Bootstrap JavaScript components not working" issues?

Bootstrap JS glitches usually come from messed-up script order, missing Popper, or wrong data attributes. Quick fixes get modals, dropdowns, and tooltips running smoothly again.​Most often, it's scripts not loading right: Popper.js before Bootstrap bundle, all at the page bottom, no duplicates or jQuery clashes (BS5 ditched jQuery). Peek at browser console for "bootstrap undefined" errors, swap old data-* to data-bs-* for BS5, clear cache, and test incognito. Boom, components wake up every time.​

Code

<link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/css/bootstrap.min.css" rel="stylesheet">
<script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/js/bootstrap.bundle.min.js"></script>

<button data-bs-toggle="modal" data-bs-target="#test">Test</button>


<div class="modal fade" id="test" tabindex="-1">
  <div class="modal-dialog">
    <div class="modal-content p-4">
      <h5 class="modal-title">Modal Working!</h5>
    </div>
  </div>
</div>