Some events don't have their attribute counterparts, one such example is focusout. Maybe it would be better if VanJS just bound all events handlers (properties starting with on whose value is a function) using addEventListener instead of relying on the DOM properties.

This would also make event names case insensitive (I like to use camelCase for event names).

Jsfiddle: https://jsfiddle.net/uqbt36mz/4/