What is the use of WebSocket in html5
Editor to share with you what is the use of WebSocket in html5, I believe most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to know it!
What is WebSocket?
The server and client of WebSocket can communicate in both directions and allow cross-domain communication. Supported by HTTP/1.1 's Upgrade mechanism and communicating through ws (non-encrypted) or wss (encrypted) protocols
WebSocket WebSocket (in DOMString url, in optional DOMString protocols); WebSocket WebSocket (in DOMString url, in optional DOMString [] protocols); WebSocket in HTML5
HTML5 only focuses on API on the client side, while each language implements it on the server side.
/ / create an Socket instance var socket = new WebSocket ('ws://localhost:8080'); / / Open Socket socket.onopen = function (event) {/ / send an initialization message socket.send (' I am the client and I\'m listeningrequests'); / / listen for message socket.onmessage = function (event) {console.log ('Client received a message',event);} / / turn off monitoring Socket socket.onclose = function (event) {console.log ('Client notified socket has closed',event);}; / / close Socket.... / / socket.close ()}
Event
Onclose onerror onmessage onopen
Attribute
ReadyState: CONNECTING 0 OPEN 1 CLOSING 2 CLOSED 3
BinaryType: String Blob ArrayBuffer
Compatibility
Method 1:
If the client does not support WebSocket, there are several candidates for Flash Socket AJAX long-polling AJAX multipart streaming IFrame JSONP polling
Method 2
Using Socket.io to smooth out the differences, the library can automatically connect with a message push method supported by the browser when the browser does not support WebSocket. The library will also detect whether the connection is dropped and automatically reconnect for you when it is dropped.
/ / create a Socket.IO instance and establish a connection var socket= new io.Socket ('localhost', {port: 8080,}); socket.connect (); / add a connection listener socket.on (' connect',function () {console.log ('Client has connected to the server');}); / / add a connection listener socket.on ('message',function (data) {console.log (' Received a message from the server listener data);}) / / add a listener socket.on ('disconnect',function () {console.log (' The client has disconnect');}) that closes the connection; / / send a message via Socket to the server function sendMessageToServer (message) {socket.send (message);} advantage
Real-time two-way communication
Good native support for browsers (compatibility can be easily solved with third-party libraries)
Support for custom protocols
Practical application
Chatting room
Server message push
Front and rear real-time system
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