title: How do I get a Javascript runtime interpreter installed on OS X?
body: <p>With OS X Xcode installed one can run ruby code in terminal with ">ruby somefile.rb" command  (or from inside TextWrangler with the run command). You can also run a ruby interpreter from in terminal and type code in single lines while the interpreter retains variable objects.</p>
  
  <p>Want same possibilities for Javascript. What must I install (if anything) on OS X to have that functionality? Not looking for an IDE as such just an interpreter that will run in Terminal.app?</p>
  
  <p>I assume this is an allowed question for Stackoverflow based on other allowed questions about IDEs for various languages like:
  <a href="https://stackoverflow.com/questions/893162/whats-a-good-ide-for-python-on-mac-os-x">What&#39;s a good IDE for Python on Mac OS X?</a></p>