title: NuxtJS/VueJS: How to know if page was rendered on client-side only?
body: <p>Currently I create a html5 video player component for an universal nuxtjs/vuejs app.
  There is an autoplay attribute for the video tag to start videos after navigate to them.
  Usually browsers don't do that directly after page load, it's prohibited.
  I need a variable in my component to know if autoplay will be possible to style elements based on this information.
  In other words: The variable should be true if the current page was only rendered on client-side, but false if it was rendered on server-side first.</p>
  
  <p>It's not possible to work with "window.history.length" because the autoplay will also not be possible after refresh, although this would not have an effect on the history length.</p>
  
  <p>Also it's not possible to set a variable in the "created" method since it will be called on server- and client-side too.</p>