title: How to run javascript snippets in firefox/chrome from a script
body: <p>I am currently trying to learn javascript. Coming from a python/R background I find it really useful for learning purposes to be able to write code in a script in Rstudio/pyCharm   which I can then execute in a interpreter by highlighting specific lines of code and then pressing a ctrl+enter or some other keyboard shortcut. </p>
  
  <p>The console available on firefox/chrome seems incredibly rich and useful for learning / testing specific pieces of code but I find it quite limiting that I can't store each line in a script with comments/notes to myself. </p>
  
  <p>Is there a way to run lines of javascript in firefox/chrome like pycharm &amp; rstudio can  with their respective interpreters  or how is it usually recommend for people to learn the language in an efficient manner ? </p>