The children property returns an array of elements, like so:
parent = document.querySelector('.parent'); children = parent.children; // [<div class="child1">] querySelector is relatively new and not supported in older browsers. There are alternatives to querySelector, like document.getElementsByClassName('parent')[0] if you so desire.
Edit: Now that I think about it, you could just use querySelectorAll to get decendents of parent having a class name of child1:
children = document.querySelectorAll('.parent .child1'); The difference between qS and qSA is that the latter returns all elements matching the selector, while the former only returns the first such element.