chrome window.open onload handler

I’m executing the following (modified for demo) script in the console of x.com

There is no cross-domain issues. But the function executes immediately – which results in an error because the DOM is not loaded (I can see visually).

If I set a timeout setTimeout(parsefn,9000) (ensuring dom is loaded), it works fine.

If I execute newWindow.onload() after dom load, it works fine.

Reading stackoverflow and what not – indicates the code should be working … ? How do I get the code to work – that is execute the function when the child window dom is loaded.

On the latest version of Chrome browser.

let newWindow;
function tweetGet(url wait) {
  newWindow = window.open(url,'_blank',"status,heigh​t=600,width=800");
  const parsefn = function(event) {
    const tweet = [url];
    tweet.push(newWindow.document.querySelectorAll("time")[0].getAttribute("datetime"));
    newWindow.close();
    console.log(tweet);
  }
  newWindow.document.body.onload = parsefn; 
}
tweetGet("https://x.com/VillaCollegeMv/status/1817893326437425374")