True, but my thinking is that .contains() is still in the ["experimental"](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/contains) [phase](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/contains). Yes, we are FxOS and don't need to worry about compatibility, but I try to use standard stuff when I can.