PhantomJS provides a headless WebKit browser with a JavaScript API

PhantomJS is a headless WebKit scriptable with a JavaScript API. It has fast and native support for various web standards: DOM handling, CSS selector, JSON, Canvas, and SVG.

Source: PhantomJS | PhantomJS

I’ve mentioned this before but we all need a reminder now and then. This looks useful for testing complex interactions on Drupal pages, among other Drupal things.