title: WKWebView xmlhttprequest with file url
body: <p>I am migrating from UIWebView to WKWebView with my local HTMLs in the app documents folder.
  I can load the index page with all css and js files, but every ajax call (xmlhttprequest) fails because of allowed-access-origin.</p>
  
  <p>I don´t want to use a webserver in my application, because I think it would be oversized. How can I make it possible? The app is a simple HTML5 application for an in house app. The device can´t get online or anything so security could be disabled completly.</p>