evaluateOnNewDocument is broken on firefox

Steps to reproduce

Tell us about your environment:

• Puppeteer version: 5.0.0 (and 3.3.0)
• Platform / OS version: MacOS 10.15.5
• Node.js version: v12.14.0

What steps will reproduce the problem?

1. Run this code

const puppeteer = require('puppeteer');

(async () => {
  const browser = await puppeteer.launch({
    product: 'firefox',
  });
  const page = await browser.newPage();
  await page.evaluateOnNewDocument(() => {
    window.addEventListener('DOMContentLoaded', () => console.log('Loaded!'));
  });
  page.on('console', (msg) => console.log(msg.text()));
  await page.goto('http://example.com');

  await browser.close();
})();

What is the expected result? Print Loaded!on console.

What happens instead? It doesn’t print Loaded!

Note: It works on chrome.

[mjzffr]

@elharrak-bouygues That’s right, Firefox support is still experimental. I’m not aware of a specific timeline, but this part of the protocol has a higher priority than other features.

[mjzffr]

The corresponding protocol-level work in Firefox is tracked at https://bugzilla.mozilla.org/show_bug.cgi?id=1601695