Show child div on mouse hover of parent - needs javascript?

Question

I need to show a div when you house over its parent (default is for the child div to be hidden). Is the only way to do this with javascript? Thanks

Answer 1

No JS required.

.hidden {
  display: none;
}

.parent:hover .hidden {
  display: block;
}

  
Hello, I'm a child...
  
..and so am I but I'm hidden.