Bootstrap hamburger and jquery versions

Hi. I’ve been building a navigation bar in CodePen for my portfolio page and following some templates/examples for creating one that collapses into a hamburger when the screen size decreases.

I’ve got it working now, but what I don’t understand is why I need:

<script src=""></script>

and not the version CodePen loads through its “Add External JavaScript” option, i.e.:

<script src=""></script>

You can see my pen (very much a WIP) if need be at

That never even occurred to me! Thanks so much for the help :smile: