Cookies are the most secure way to do sessions/logins in the browser but this MDN article says Cookies are "old-fashioned", have security problems, and the only reason new websites use them is because of developer habits…

Peer-to-Peer Communications with WebRTC

Comprehensive guide on the JavaScript tooling ecosystem by MDN.

New Tutorial on MDN: Spicy HTML-first JavaScript framework: EmberJS

Firefox (75+) now supports native lazy loading of images

HTTP 402: Payment Required

CSS Containment Specification

HTTP 418: I'm a Teapot

Contributing to the Mozilla Code Base

Marquee HTML Element

MDN (beta) is now built with React

WebAssembly (MDN Web Docs)

Privacy and the :visited selector (2010)

Plugin Roadmap for Firefox

Power Profiling Overview

CSS Layout cookbook

Storage access policy: Block cookies from trackers – Mozilla – MDN

OffscreenCanvas: Canvas within a Web Worker

Effectively supported in all browsers, JavaScript has its own form of media queries just like CSS.

HTTP 418 I'm a Teapot

WebReplay – Time Travel Debugging for Firefox

Firefox 61: Accessibility Inspector

<base>: The Document Base URL Element – HTML – MDN

Console.table()

Pluralization rules around the world

Web Authentication API – Web APIs – MDN

Using shadow DOM - Web Components

ES2015 / ES6 modules are now live in Firefox 60

SpiderMonkey: Tracing JIT

HTML5 forms (2017)

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