<button id="myBtn">Click me!<button>
// somewhere in the top level of app.js
const btn = document.getElementById('myBtn');
btn.addEventListener('click', doClick, false);
MDN: EventTarget.addEventListener
Phoenix uses a bundler (Phoenix < 1.4 ? Brunch : webpack 4). This deliberately keeps everything out of the global space so the markup can’t find that function. Meanwhile JavaScript has no problem reaching into the DOM.
