PhantomJS : PhantomJS is a headless WebKit with JavaScript API. It has fast and native support for various web standards: DOM handling, CSS selector, JSON, Canvas...
SPOFCheck : A CLI tool for detecting frontend SPOF, mainly blocking scripts and CSS
boomerang : boomerang is a piece of javascript that you add to your web pages, where it measures the performance of your website from your end user's point of vie...
Rich tools for instrumenting, analyzing, and visualizing web apps.