Uncaught TypeError: Property 'handleEvent' is not callable. Range.js

[cojoclaudiu]

Hello, any help with this issue?

I'm using Firefox.

Thank you

[pheek]

Similar error here (also firefox): When the following *.js-File is loaded, the same error occurs:

function doSomething() {
  console.log("DOM is loaded now.");
}

document.addEventListener("DOMContentLoaded", new doSomething);

First prints "DOM is loaded now. But then leads to the error
Uncaught TypeError: Property 'handleEvent' is not callable.