title: Is there any EventEmitter in browser side that has similar logic in nodejs?
body: <p>It is so easy to use eventEmitter in node.js:</p>
  
  <pre><code>var e = new EventEmitter();
  e.on('happy', function(){console.log('good')});
  e.emit('happy');
  </code></pre>
  
  <p>Any client side EventEmitter in browser native?</p>