How To Make Reuseable HTML Navigation Menus?

Question

I\'m sure this topic comes up all the time,
But I can\'t seem to fine a concise answer.

I\'ve got a vertical menu bar that I want to reuse in webpages (>20)

Answer 1

As a modern answer to a six year old question: Web Components are specifically reusable HTML components, and Polymer is possibly the most popular implementation of it at the moment. Currently virtually no browser has native support for Web Components, so at the very least a Javascript polyfill is required.