title: Populating input text field in WKWebView
body: <p>I have loaded the following html page in a <strong>WKWebView</strong> controlled by a specific view controller. <strong>After</strong> the view is loaded I would like that the App automatically populates an input text field in the page.</p>
  
  <p>In this example I would like the app to write "Hello Result" in the "Result" text field of the form below.</p>
  
  <pre><code>&lt;html&gt;
  &lt;head&gt;
      &lt;title&gt;Test Page&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
  &lt;form&gt;
   QR Result &lt;input type="text" name="Result" width="20"&gt;
  &lt;/form&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>This is the code where I load the <strong>HTML page as file</strong> within the view controller:</p>
  
  <pre><code>   var htmlFile = NSBundle.mainBundle().pathForResource("apptest", ofType: "html")
          var contents = NSString(contentsOfFile: htmlFile!, encoding: NSUTF8StringEncoding, error: nil)
          self.webView?.loadHTMLString(contents!, baseURL: nil)
  </code></pre>
  
  <p>It doesn't matter how I load the view (file or URL). What I want to be able to do is to fill the field at some point <strong>after</strong> loading the view.</p>