Monitor all Events on an Element

I've recently started researching autofill and what hints that browsers give to developers that they have automatically filled in a form field on the users behalf. Blink and WebKit browsers have a special CSS pseudo class that you can look at (more in another post), but firefox doesn't. There must be some event!!!

Chrome DevTools has a handy helper function called monitorEvents, you call it with an element as an argument and it will then log to the console all the events that happen on that element. Meggin Kearny on our team and Flavio Cotes wrote about monitorEvents and all the other helper functions recently on our WebFundamentals site.

Firefox DevTools don't have this utility function, so I wrote my own.

There are no guarantees for accuracy, but it worked for me ;)

function monitorEvents(element) {
  var log = function(e) { console.log(e);};
  var events = [];

  for(var i in element) {
    if(i.startsWith("on")) events.push(i.substr(2));
  }
  events.forEach(function(eventName) {
    element.addEventListener(eventName, log);
  });
}

If you are a person who likes gists, then here you go.

About Me: Paul Kinlan

I lead the Chrome Developer Relations team at Google.

We want people to have the best experience possible on the web without having to install a native app or produce content in a walled garden.

Our team tries to make it easier for developers to build on the web by supporting every Chrome release, creating great content to support developers on web.dev, contributing to MDN, helping to improve browser compatibility, and some of the best developer tools like Lighthouse, Workbox, Squoosh to name just a few.