title: reCAPTCHA does not work in iOS 10 UIWebView
body: <p>My site is using reCAPTCHA v2.</p>
  
  <p>In the iOS 10 UIWebView, I can not go to the next step when I check "I am not Robot".</p>
  
  <p>However, iOS 10 WKWebView works well.
  Also, iOS 11 or later UIWebView works well.
  The problem only occurs in iOS 10 UIWebView.</p>
  
  <p>Does anyone know how to fix it?</p>