Excellent reminder of why we need to progressively enhance and not have our site's core functionality relying on JavaScript:

  1. The browser doesn’t recognise your JavaScript code
  2. Browser extensions can break JavaScript
  3. Some browsers turn off JavaScript on slow connections
  4. JavaScript might fail to download
  5. Corporate firewalls and mobile operators block JavaScript
  6. Some browsers don’t run JavaScript

Adam's post goes into detail on each point and includes "what to do about it"

Source: adamsilver.io