title: Selenium - {[[PromiseStatus]]: "pending"} has no method 'indexOf'
body: <p>I totally understand want is happening, but can't find a way around the issue. 
  Here is the code : </p>
  
  <pre><code>el    = driver.findElement(By.css('#mailmillieu a'));
  text  = el.getAttribute("href"); 
  text  = fqdn + text.substring( text.indexOf("/parse_actions") );
  driver.get(text);
  </code></pre>
  
  <p>Here is the error message : </p>
  
  <pre><code>TypeError: Object Promise::340 {[[PromiseStatus]]: "pending"} has no method 'indexOf'
  </code></pre>
  
  <p>How can I tell Selenium to wait until the promise is fullfilled or rejected?</p>