title: Hide element if other class exist
body: <p>i know how to do it with <code>jquery</code>, but how with clean <code>javascript</code>? Any help how to do this?</p>
  
  <p>Here is my code</p>
  
  <pre><code>var element = document.getElementsByTagName('tagone')[0];
  
  if(element !== null){ 
       document.getElementByClassName('classsix')[0].style.display = 'none';
  }
  </code></pre>