title: How did Facebook detect that my browser window needs to be closed?
body: <p>Before my post might get deleted or buried, allow me to point out that <strong>I'm not asking for troubleshooting help. I'm just curious for a technical explanation.</strong></p>
  
  <p>So I'm on Chrome and today, when browsing Facebook, the site showed me an in-page, Facebook-styled, dialog with the following error message:</p>
  
  <p><code>Sorry, something went wrong, Please try closing and re-opening your browser window.</code></p>
  
  <p>At first I thought this might have something to do with some exception being caught at some point and the devs pointing the user to re-initialze the page. So I refreshed the page, but I found the same error message waiting for me. I then moved on to close the current Chrome tab, opened a new one and went to Facebook again, only to see the error message again. Only indeed closing the actual browser window and re-opening fixed the error.</p>
  
  <p>This made me wonder: what type of logic lives in my browser window compared to the page in a tab? How did the Facebook application gain access to objects on window level rather than being sandboxed to its own page? Doesn't Facebook just use Javascript or something that relies on JS - presumably ReactJS?</p>
  
  <p>Thanks to anyone who can explain this to me.</p>