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EventSource: readyState property

files/en-us/web/api/eventsource/readystate/index.md

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{{APIRef("Server Sent Events")}}{{AvailableInWorkers}}

The readyState read-only property of the {{domxref("EventSource")}} interface returns a number representing the state of the connection.

Value

A number which is one of the three possible state constants defined on the {{domxref("EventSource")}} interface:

  • EventSource.CONNECTING (0)
    • : The connection is not yet open.
  • EventSource.OPEN (1)
    • : The connection is open and ready to communicate.
  • EventSource.CLOSED (2)
    • : The connection is closed or couldn't be opened.

Examples

js
const evtSource = new EventSource("sse.php");
console.log(evtSource.readyState);

[!NOTE] You can find a full example on GitHub — see Simple SSE demo using PHP.

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

  • {{domxref("EventSource")}}