Why is Event.target not Element in Typescript?

I simply want to do this with my KeyboardEvent

var tag = evt.target.tagName.toLowerCase();

While Event.target is of type EventTarget, it does not inherit from Element. So I have to cast it like this:

var tag = (<Element>evt.target).tagName.toLowerCase();

This is probably due to some browsers not following standards, right? What is the correct browser-agnostic implementation in TypeScript?

P.S. I am using jQuery to capture the KeyboardEvent.