从服务器获取刷新数据

Question

How can i get latest or fresh data from server (if in server happened new event (for example there are 2 users x,y and x send messages to y and y get this message without refreshing page ) )? I don't want to use setInterval because it repeats all message again and again. Is there any Technique that can i use for this ? I heard about Ajax that technique need to send request to the server but i want when happen an event in the server and webpage get it without refreshing..

Answer 1

The first technique is the long polling, which sends request to the server and waits until the server sends something, for example the new message. You must re-send requests to the server each time you get a new message or your request is time out. This technique uses AJAX. Long polling PHP example - How do I implement basic "Long Polling"?

The second is web sockets, https://en.wikipedia.org/wiki/WebSocket

this stackoverflow question deals with the implementation of websocket.

socket.io has a demo of chat application.