title: Appendchild based on data-attribute
body: <p>I've got a few divs like this:</p>
  
  <pre><code>&lt;div id="thisisme" data-order="1"&gt;
  &lt;div id="thisisme" data-order="2"&gt;
  </code></pre>
  
  <p>I want to add some content to the specific div with data-order = 1. The Javascript-code:</p>
  
  <pre><code>var hello = document.getElementById('thisisme');
  thisisme.textContent = "blabla"; 
  hello.appendChild(thisisme);
  </code></pre>
  
  <p>This will add it to both divs. But I only want to add the content to div number 1. How can I make this happen?</p>