Creating an event listener code example

Example 1: javascript custom events with data

//Listen for the event
window.addEventListener("MyEventType", function(evt) {
    alert(evt.detail);
}, false);

//Dispatch an event
var evt = new CustomEvent("MyEventType", {detail: "Any Object Here"});
window.dispatchEvent(evt);

Example 2: js addeventlistener

var element=document.getElementById("some_id");
var listener=element.addEventListener('click',function(event){                          
            
 });