title: Click on Button Class or Span class
body: <p>I want to simulate a click on a button up or down, </p>
  
  <p>I tried with this :<code>document.querySelector('button.up')[4].click();</code></p>
  
  <p>in the page there is few input field with up and down button, I would like the button up of the field with id "sl" or nth up button ? 
  the code : </p>
  
  <pre><code>&lt;div class="input-text num" &gt;
  &lt;input type="text" placeholder="" id="sl" min="0" max="" step="0.00001"&gt;
  &lt;button tabindex="-1" class="up"&gt;
  &lt;span class="v"&gt;&lt;/span&gt;&lt;/button&gt;&lt;
  button tabindex="-1" class="down"&gt;
  &lt;span class="v"&gt;&lt;/span&gt;&lt;/button&gt;&lt;/div&gt;
  </code></pre>