title: Using javascriptExecutor to find a WebElement
body: <p>The title says all, I need a way to select a WebElement.</p>
  
  <p>I am using Firefox Quantum (latest beta version).</p>
  
  <p>This is what I tried.</p>
  
  <pre><code>String ccNumberSelector = "'#card_details &gt; div &gt; input'";
                              Object ccNumberField = js.executeScript("return $(" + ccNumberSelector + ").eq(0);");
                              ((WebElement) ccNumberField).sendKeys("some key sequence"); 
  </code></pre>
  
  <p>All that this does is 'freeze' (not really freeze, it just blocks the whole webpage, like you can't interact with it anymore).</p>
  
  <p>What am I doing wrong?</p>
  
  <p>PS: I CANNOT use any other selector than this (id's and everything else are random).</p>