I have an application form on a web page that sometimes does not submit correctly on Edge, it instead reloads the page.

It works perfectly in Chrome every time.

I have since worked out that the issue is that the page does not always fully load and the submit listener relies on this.

I can hit Ctrl F5 3 or 4 times in a row and it does not load, then on the 5th it does.

There are no errors in the console to suggest what might be going on.

Any clues as to what is going on would be very welcomed.

window.addEventListener('load', function() {
  var forms = document.getElementsByClassName('needs-validation');
  // Loop over them and prevent submission
  var validation = Array.prototype.filter.call(forms, function(form) {
    form.addEventListener('submit', function(event) {
    let err = false;