Saved from https://javascript.info/dispatch-events

dispatchEvent

<button id="elem" onclick="alert('Click!');">Autoclick</button>

<script>
  let event = new Event("click");
  elem.dispatchEvent(event);
</script>

<h1 id="elem">Hello from the script!</h1>

<script>
  // catch on document...
  document.addEventListener("hello", function(event) { // (1)
    alert("Hello from " + event.target.tagName); // Hello from H1
  });

  // ...dispatch on elem!
  let event = new Event("hello", {bubbles: true}); // (2)
  elem.dispatchEvent(event);

  // the handler on document will activate and display the message.

</script>

  static async setInputValue(input, value, delay, dispatchEvent=true) {
    if (value === undefined) return input;

    input.type === 'select-one' ? input.value = value : await this.type(input, value, delay);

    if (dispatchEvent) {
      input.dispatchEvent(new Event('change'));
    }
    return input;
  }