I'd wager most of us are happy with the concept that it's being presented on CodePen with a bit of helper JS so that the target audience (developers who are unlikely to disable JS, or are happy to enable it for a site like CodePen) can better appreciate the demo.
I'd wager most of us are happy with the concept that it's being presented on CodePen with a bit of helper JS so that the target audience (developers who are unlikely to disable JS, or are happy to enable it for a site like CodePen) can better appreciate the demo.