Trigger an event in plain.JS #Javascript

function for trigger event

function triggerEvent(el, type) {
  if ('createEvent' in document) {
    // modern browsers, IE9+
    var e = document.createEvent('HTMLEvents');
    e.initEvent(type, false, true);
    el.dispatchEvent(e);
  } else {
    // IE 8
    var e = document.createEventObject();
    e.eventType = type;
    el.fireEvent('on' + e.eventType, e);
  }
}