title: server send push notification to client browser without using polling
body: <p>I am developing a web app in which I want that when some changes in database occurs, server sends response to particular client(<strong><em>like push notification</em></strong>). And I want this notification to be sent client's browser. I don't want to use polling.</p>
  
  <p>What can I do?
  I think it's possible using <a href="http://www.html5rocks.com/en/tutorials/eventsource/basics/" rel="nofollow noreferrer"><strong>SSE</strong></a>, but I am not clear.<br>
  I want to know<br></p>
  
  <ul>
  <li>Is it possible to send response to particular client without client's request(without polling).</li>
  <li>How server will detect that particular client?</li>
  </ul>
  
  <p>please help me.</p>