grunt : Grunt is a task-based command line build tool for JavaScript projects
tracing-framework : Rich tools for instrumenting, analyzing, and visualizing web apps.
JSHint : A JavaScript Code Quality Tool. JSHint is a tool that helps to detect errors and potential problems in your JavaScript code.
DOM Monster Bookmarklet : DOM Monster is a cross-platform, cross-browser bookmarklet that will analyze the DOM & other features of the page you're on, and give you its bill of ...