How to use HTML5 server-sent events -

Server-sent events is an HTML5 technology which allows a client to automatically monitor event notifications from a server, and react as needed. This technology is very useful to notify live events, to implement, for example, a live messaging application or a news feed. In this tutorial we will see how to implement this technology using PHP and javascript.
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The example with animals is not working. I changed the file “animals.php” and nothing happens