HTML SSE

HTML5 Server-Sent Events

Server-Sent Events - One Way Messaging

 A server-sent occasion is the point at which a web page naturally gets refreshes from a server.

This was likewise conceivable some time recently, however the web page would need to inquire as to whether any updates were accessible. With server-sent occasions, the updates come consequently.

Cases: Facebook/Twitter refreshes, stock value refreshes, news sustains, don comes about, and so forth.

Browser Support

Receive Server-Sent Event Notifications

Example

var source = new EventSource("demo_sse.php");
source.onmessage = function(event) {
    document.getElementById("result").innerHTML += event.data + "<br>";
};

Yourself Try

Check Server-Sent Events Support

In the tryit example above there were some extra lines of code to check browser support for server-sent events:

if(typeof(EventSource) !== "undefined") {
    // Yes! Server-sent events support!     // Some code..... } else {
    // Sorry! No server-sent events support.. }

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Server-Side Code Example

For the example above to work, you need a server capable of sending data updates (like PHP or ASP).
The server-side event stream syntax is simple. Set the "Content-Type" header to "text/event-stream". Now you can start sending event streams.
Code in PHP (demo_sse.php):

<?php
header('Content-Type: text/event-stream');
header('Cache-Control: no-cache');

$time = date('r');
echo "data: The server time is: {$time}\n\n";
flush();
?>

Code in ASP (VB) (demo_sse.asp):

<%
Response.ContentType = "text/event-stream"
Response.Expires = -1
Response.Write("data: The server time is: " & now())
Response.Flush()
%> 

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