FWIW there's nothing about "vanilla JavaScript" that means IE9 will be supported. It's avoiding certain language features and DOM APIs that does it. Just addin

FWIW there's nothing about "vanilla JavaScript" that means IE9 will be supported. It's avoiding certain language features and DOM APIs that does it. Just adding this because it can lead to the implication that not supporting IE9 means you're trying to do something frivolous as opposed to "vanilla JavaScript".