title: check if webView can login
body: <p>I'm making an app where users uses a custom view to login into a website. I got everything working, from passing the data from UITextFields to webView website, also i can submit the login and username using this code</p>
  
  <pre><code>NSString *performSubmitJS = @"var passFields = document.querySelectorAll(\"input[type='submit']\"); \
  passFields[1].click()";
  [webView stringByEvaluatingJavaScriptFromString:performSubmitJS];
  </code></pre>
  
  <p>How can I check if the user introduced wrong username and password? is there anyway to use something like </p>
  
  <pre><code>document.querySelectorAll
  </code></pre>
  
  <p>to check if user introduced wrong credentials?</p>