Brush up on web platform basics

When's the last time you read web platform documentation like the Mozilla Developer Network HTML or JavaScript references for fun? A good practitioner deeply understands the tools they work with, but it's easy to get stuck in a rut, reusing what we know, while the platform continues to evolve without us. We're not often allocated time to hone these basic skills, or discover new facets of tools we might consider old friends (or frenemies, as the case may be). Let's take some time to revisit the basics of HTML and JavaScript by focusing on a selection of features available in any browser these days, which may not have been around, or used commonly, when you were learning the web platform.