PUBLIC MARKS with tag polyfill

test whether a CSS media type or media query applies

In your animation work, you've used a timer loop to make changes every few milliseconds. Good for us: browser vendors have decided, "hey, why don't we just give you an API for that, because we can probably optimize some things for you." So it's basic API for use with animation, whether that be DOM-based styling changes, canvas or WebGL.

A tiny, no-frills, framework-independent, targeted overflow: auto polyfill for use in responsive design.

Look up HTML5 features, know if they are ready for use, and if so find out how you should use them – with polyfills, fallbacks or as they are