title: Curious about the new way YouTube is loading pages
body: <p>I've noticed when I'm watching a video and I click on the logo or a related video that a red progress bar (above the logo) dashes across the screen. At the same time there is a slight overlay to "grey" out the content then it fades in the new page. FYI, the URL changes to the new URL before the progress bar and transition happens. </p>
  
  <p>The div ID of that bar is progress. Looks like some kind of cool jQuery ajax load but changing pages. I don't know.</p>
  
  <p><img src="https://i.stack.imgur.com/BUqey.jpg" alt="enter image description here"></p>