title: Avoid browser popup blockers
body: <p>I'm developing an OAuth authentication flow purely in JavaScript and I want to show the user the "grant access" window in a popup, but it gets blocked.</p>
  
  <p>How can I prevent pop up windows created by either <code>window.open</code> or <code>window.showModalDialog</code> from being blocked by the different browsers' pop-up blockers?</p>