Developer Builds Zero-Dependency Firefox New Tab Extension in Vanilla JavaScript

A developer documented building Weather & Clock Dashboard, a Firefox extension, using only HTML, CSS, and JavaScript with no frameworks, build tools, or dependencies. The author chose this approach to keep the extension under 100KB, avoid breakage from dependency updates, and make it easier for web developers to contribute. The write-up explains the basic extension structure, including a manifest.json file that overrides the new tab page. It also shows how the extension uses OpenWeatherMap's free API, native time zone handling, system dark mode detection, and localStorage caching to keep loading fast.