I don't think the ECMA definition of JavaScript has much of an effect on the shape of the internet. Also to be clear browser engines are not internally implemented in JavaScript, but in languages like C++.
The Web Platform specs, that's a different story though - those have 100% effect on the shape of the Internet with multiple standardization organizations (the main one being W3C). See https://developer.mozilla.org/en-US/docs/Learn/Getting_started_with_the_web/The_web_and_web_standards