title: How to calculate content height of WKWebView?
body: <p>For UIWebView, we can get content height by this:</p>
  
  <pre><code>[webView stringByEvaluatingJavaScriptFromString:@"document.body.offsetHeight"]
  </code></pre>
  
  <p>But WKWebView doesn't have this method and webView.scrollView.contentSize.height is not right.</p>
  
  <pre><code>(void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation
      {
      }
  </code></pre>
  
  <p>Thank you for your help!</p>