const EventEmitter = require('events');

class Client extends EventEmitter
{
    eventTest() {
        this.emit('event');
    }
}

let testClient = new Client(1,2,3,4,5);
testClient.once('event', () => {console.log('triggerd1!')} );
testClient.on('event', () => {console.log('triggerd2!')} );
testClient.eventTest();
testClient.eventTest();

> b = a.c || 4;
4

<a href="#" class="deleteUser" data-id="33" />

// Now we can take it with JQuery like this: 
$('.deleteUser').on('click', function() {
  $(this).data('id')
});