dom - Finding child element of parent pure javascript

Question

What would the most efficient method be to find a child element of (with class or ID) of a particular parent element using pure javascript only. No jQuery or other frameworks.

In this case, I would need to find child1 or child2 of parent, assuming that the DOM tree could have multiple child1 or child2 class elements in the tree. I only want the elements of parent

    <div class="parent">
        <div class="child1">
            <div class="child2">
            </div>
        </div>
    </div>

Answer 1

If you already have var parent = document.querySelector('.parent'); you can do this to scope the search to parent's children:

parent.querySelector('.child')