Failed To Execute 'addeventlistener' On 'eventtarget'

I struggle with a javascript error, that I cannot get rid of: Uncaught TypeError: Failed to execute 'addEventListener' on 'EventTarget': The callback provided as parameter 2 is not

Solution 1:

The 2nd parameter of window.addEventListener should be a function.

What you have boils down to:

window.addEventListener("load", setTimeout(function(){ /* stuff */}, 3000));

That setTimeout is called the moment you call addEventListener, and the return value of setTimeout (The timeout id) is passed to addEventListener.

You need to wrap the setTimeout in a function:

window.addEventListener("load", () =>setTimeout(function(){
    /* stuff */
}, 3000));

Now, you're passing a function to addEventListener that can be called on the load event. That function will set a new timeout.