Creating an event in javascript and firing it programmatically

customeEvents.js

// creating an event and firing it programmatically
document.addEventListener('change', function(e) {
  console.log(e.someProp); 
}); 

var event1 = document.createEvent('HTMLEvents');
event1.initEvent('change',true,false);
event1.someProp = 'yourPropHere';

inputEl.dispatchEvent(event1);  


// Polyfill from MDN, see: https://developer.mozilla.org/en/docs/Web/API/CustomEvent
(function () {
  function CustomEvent ( event, params ) {
    params = params || { bubbles: false, cancelable: false, detail: undefined };
    var evt = document.createEvent( 'CustomEvent' );
    evt.initCustomEvent( event, params.bubbles, params.cancelable, params.detail );
    return evt;
   };

  CustomEvent.prototype = window.Event.prototype;

  window.CustomEvent = CustomEvent;
})();

document.addEventListener('name-of-event', function(e) {
  console.log(e.detail); // Prints "Example of an event"
});

// Create the event
var event = new CustomEvent('name-of-event', { 'detail': 'Example of an event' });

// Dispatch/Trigger/Fire the event
document.dispatchEvent(event);