How to target child div by Javascript?

Issue

I want to apply JavaScript on sticky header in my site. For this I want to target a div inside sticky div by JavaScript. Please let me know how to target a dive that is inside some other divs by JavaScript.

var yourHTML = '<div class="mynewdiv">Test</div>';
document.getElementsByClassName('at-sticky' 'custom-logo-link') 
[0].innerHTML = yourHTML;

<div class="at-sticky"> 
  <div class="container"> 
    <div class="navbar-header"> 
      <a href="#" class="custom-logo-link" 
      rel="home" itemprop="url">
        <img src="#" class="custom-logo">
      </a>
    </div>
  </div>
</div>

Solution

You can try with Document​.query​Selector() which allows CSS like selector:

var yourHTML = '<div class="mynewdiv">Test</div>';
document.querySelector('.at-sticky .custom-logo-link').innerHTML = yourHTML;

<div class="at-sticky"> 
  <div class="container"> 
    <div class="navbar-header"> 
      <a href="#" class="custom-logo-link" 
      rel="home" itemprop="url">
        <img src="#" class="custom-logo">
      </a>
    </div>
  </div>
</div>

Answered By - Mamun