title: Google Apps Script - Using Google's file picker on a standalone script
body: <p>I'm creating a application that requires the user to select a folder from their Drive. I'm struggling to set up the Picker API.</p>
  
  <p><a href="https://developers.google.com/picker/docs/" rel="nofollow noreferrer">Following this documentation</a> I set up my project using their 'Hello World' script but after changing the 'devlopedKey' and 'clientID', I test the code to receive the error:</p>
  
  <p>Error 401, invalid_client, no registered origin.</p>
  
  <p>After searching around I found suggestions to set the Authorised JavaScript origin within the client credential to <a href="http://localhost:8888" rel="nofollow noreferrer">http://localhost:8888</a>. After doing this I receive a different error:</p>
  
  <p>Error 400, origin_mismatch </p>
  
  <p>Sorry if this is a simple mistake of mine, any help would be appreciated.</p>