Usually one uses text editor to create source files (like JavaScript). I use VisualStudio which have intellisence supprt for JavaScript, but any other editor will do (vim or notepad on Windows are both fine).
To run JavaScript by itself you need something that can do that. I.e. on Windows you can directly run script from console using CScript script.js
command. There are other ways to run JavaScript on Windows and other OS.
Browsers (like Chrome) do not run JavaScript by itself, only as part of a page or extensions. It is unclear what one would expect of browser to do with JavaScript by itself.