Keyboard focus trap (especially useful for modals)

Live demo

Example usage

<script
  src="https://cdn.jsdelivr.net/gh/hchiam/keyboard-focus-trap@1.2.0/keyboard-focus-trap.js"
  integrity="sha384-X4CXOjFm0n6iwt8qEFOvwsXLyZonS799Q47YRuZPFQOTUHXkGlV9kXsbjpZ1S3rm"
  crossorigin="anonymous"
></script>

bash get-integrity.sh

Inspirations for this

• https://github.com/udacity/ud891/tree/9c43eae0e158718703d96ab96f8b2999f69272b2/lesson2-focus/07-modals-and-keyboard-traps/solution

• https://gomakethings.com/how-to-get-the-first-and-last-focusable-elements-in-the-dom

Caveat/gotcha

https://stackoverflow.com/questions/44452084/how-to-keep-focus-within-modal-dialog/44481275#44481275

May not work well with web components and shadow DOM, but can be overcome with custom code.