title: Server-Sent Events vs Polling
body: <p>Is there a big difference (in terms of performance, browser implementation availability, server load etc) between <a href="http://www.w3schools.com/html5/html5_serversentevents.asp" rel="noreferrer">HTML5 SSEs</a> and straight up Ajax polling? From the server side, it seems like an <code>EventSource</code> is just hitting the specified page every ~3 seconds or so (though I understand the timing is flexible). </p>
  
  <p>Granted, it's simpler to set up on the client side than setting up a timer and having it <code>$.get</code> every so often, but is there anything else? Does it send fewer headers, or do some other magic I'm missing?</p>