Try in Browser
Amok is a free open source, editor agnostic, cross-platform command line
tool for a hassle-free live development, testing and debugging workflow for web browsers.
It aims to make the development workflow feel like a native script runtime with a zero configuration development server that supports pre-processing, a read-eval-print-loop and console mirroring to standard output.
It has additional features to enable live editing, primarily hot patching which allows you to edit the source code of scripts that are currently active on the page, which will then be re-sourced while the application is running. There is also generic file watch events for handling hot swapping of resources in a domain specific manner, like reloading css, images, et cetera.