EventSource: EventSource() constructor
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since January 2020.
Note: This feature is available in Web Workers.
The EventSource()
constructor returns a newly-created EventSource, which represents a
remote resource.
Syntax
js
new EventSource(url)
new EventSource(url, options)
Parameters
url-
A string that represents the location of the remote resource serving the events/messages.
optionsOptional-
Provides options to configure the new connection. The possible entries are:
withCredentialsOptional-
A boolean value, defaulting to
false, indicating if CORS should be set toincludecredentials.
Examples
js
const evtSource = new EventSource("sse.php");
const eventList = document.querySelector("ul");
evtSource.onmessage = (e) => {
const newElement = document.createElement("li");
newElement.textContent = `message: ${e.data}`;
eventList.appendChild(newElement);
};
Note: You can find a full example on GitHub — see Simple SSE demo using PHP.
Specifications
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Browser compatibility
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EventSource() constructor
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options.withCredentials parameter
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Legend
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- Full support
- Full support