“JavaScript is a programming language that makes websites interactive. HTML & CSS will let you make nice looking webpages, but they’ll be static. JavaScript allows you to ask your user to input information, move elements around on the page, and for to make your website more modern and functional.”
#webdev
Unheap
“A tidy collection of jQuery plugins”
Emmet Documentation
Child of ZenCoding, Emmet gives you some really powerful snippet-completion powers for writings lots of HTML quickly.
Kodiak PHP
“The only iPad app with offline code execution”
Meteor
“Meteor is an open-source platform for building top-quality web apps in a fraction of the time, whether you’re an expert developer or just getting started.”
Skeleton WordPress Theme
Simple, responsive theme for WordPress. Also has a sibling project that just provides the HTML/CSS boilerplate (Skeleton) for any web site.
20+ Useful But Often Overlooked Utility Functions In WordPress
20+ Useful But Often Overlooked Utility Functions In WordPress
Nice list of WordPress stuff that people often overlook.
spin.js
Javascript-only loading spinner animation. Totally customizable. Awesome.
LiveCSS
Monitor a page and poll the CSS files associated to reload them if they change.