Hierarchic Indeterminate Checkboxes with JavaScript (Vanilla)

Earlier today Chris Coyier tweeted that he was in the process of rewriting one of his pens without jQuery: Been trying to re-write this without jQuery: https://t.co/xvsZMKsfvL I’m like 70% there but haven’t quite gotten it. jQuery is doing so much helpful DOM traversal here it’s a pain in the ass without it. — Chris …