JavaScript

Firing an ad-hoc HTTP POST from the Chrome devtools console with XMLHttpRequest, and why to load a same-origin page first.

Adding pull to refresh to a plain web page with jquery.scrollz and a few lines of jQuery bound to the pulled event.

Hubot script that pipes chat messages to a Pandorabots AI bot and returns the reply, using xml2js to parse the response.

Hubot script that takes a CloudMailin webhook and posts the email into a HipChat room, with the room ID read from the URL.

Prefilling the Fix Version field on the Jira create screen with a little JavaScript, once you dig the version ID out of the database.