title: Reloading Jupyter Widgets for rapid development
body: <p>I am currently working on a custom Jupyter Widget. When I include the necessary javascript using <code>%%javascript</code> magic in the notebook I can simply reload these cells to update my widget if I make changes, which is handy for development. </p>
  
  <p>Is there a way you can do this type of easy reloading with the javascript stored outside of the notebook? Because right now I have to completely restart Jupyter when I want to see the effects of a change.</p>
  
  <p>A related question: when I store the javascript externally, Jupyter somehow still knows where to find it even though I don't load it explicitly. Where does Jupyter look to find the javascript for custom widgets?</p>