I am trying to populate a form using JavaScript Snippets from inside of a Chromium browser (Edge). Then I want to click to submit button. I tried using document.getElementById('FieldId').value='MyValue'; The value populated, however when I click submit, the form validation function throws an error that the field is required and the form doesn't submit. So I found some JQuery that works, but my client insist that I use plain JavaScript.

The JQuery that works is:

$('#FieldId').val('MyVal');
$('#FieldId').change();

What is the JavaScript equilavent to JQuery's .change()?