Traditionally, a web page has to send a request to the server to receive new data; that is, the page requests data from the server. With server-sent events, it's possible for a server to send new data to a web page at any time, by pushing messages to the web page. These incoming messages can be treated as Events + data inside the web page.
||6.0 (6.0) 
||Firefox Mobile (Gecko)
 Firefox currently does not support EventSource in web/shared workers. and prior to version 36 server-sent events do not reconnect automatically in case of a connection interrupt.
 Opera 9 partial supports Server-sent Events.
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