This could save a lot of bandwidth and user CPU over time: “If a page is minimized or hidden behind another tab, it may not make sense to continue functionality such as polling the server for updates or performing an animation. The Page Visibility API aims to give developers information about whether or not the page is visible to the user.”
web_development
Pusher
A scalable, hosted API for realtime push messaging for Web and mobile apps, that is powered by HTML5 WebSockets. The pricing looks pretty good too.
Prefixr
Paste your CSS into Prefixr and it will automatically add vendor prefixes for CSS3 properties. Even better, there’s an API available, so you can automate the change or hook into it from your favorite IDE.
7 Chrome Tips Developers & Designers May Not Know
by @elijahmanor. Several of these were new to me. Devs should check this out.
Flexible Nav
Uses heading tags in the page to build a navigation bar on the right side of the page. Could be handy for single-page Web sites.
Sinon.JS
“Versatile standalone test spies, stubs and mocks for JavaScript…No dependencies, works with any unit testing framework.”