server sent events
server push
https://html5doctor.com/server-sent-events/
https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events
https://stackoverflow.com/questions/20123762/what-the-different-between-onmessage-and-addeventlistener
https://en.wikipedia.org/wiki/Server-sent_events
https://www.w3schools.com/html/html5_serversentevents.asp
https://apifriends.com/api-streaming/server-sent-events/
https://www.tutorialdocs.com/article/server-sent-events-tutorial.html
https://www.html5rocks.com/en/tutorials/eventsource/basics/
https://www.baeldung.com/spring-server-sent-events
EventSource
https://developer.mozilla.org/zh-CN/docs/Server-sent_events/EventSource
https://www.cnblogs.com/xgqfrms/p/11067070.html
demo
https://www.w3schools.com/html/tryit.asp?filename=tryhtml5_sse
xgqfrms 2012-2020
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