ES6学习

web Workers() 后台脚本执行

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var w;
function startWorker(){
    if(typeof(Worker) !== undefined){
        if(typeof(w) !== undefined){
            w = new Worker("demo_workers.js");
        }
        w.onmessage = function(event){
            console.log(event.data);
        }
    }else{
        console.log("你的浏览器不支持web workers...");
    }
}
function stopWorker(){
    w.terminate();
    w = undefined;
}
//demo_workers.js
var i=0;
function timedCount(){
    i=i+1;
    postMessage(i);
    setTimeout("timedCount()",500);
}
timedCount();

服务器发送事件(Server-Sent Events)

阮一峰server-sent evnets教程
服务器向浏览器推送信息

事件 描述
onopen 当通往服务器的连接被打开时执行
onmessage 当接收到消息时执行
onerror 当发生错误时执行 
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if("EventSource" in window){
    var source = new EventSource("demo_sse.php");
    source.onmessage = function(event){
        console.log(event.data);
    }
}else{
    console.log("你的浏览器不支持server-sent事件...");
}
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//php
header('Content-Type: text/event-stream');
header('Cache-Control: no-cache');

$time = date('r');
echo "data: The server time is: {$time}\n\n";
flush();

websocket

浏览器双向通信协议

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function WebSocketTest(){
    if("WebSocket" in window){
        var ws = new WebSocket("http://localhost:8080");
        ws.onopen = function(){
            ws.send("发送数据");
            alert("数据发送中...");
        }
        ws.onmessage = function(evt){
            var received = evt.data;
            alert("数据已接收...")
        }
        ws.onclose = function(){
            alert("连接关闭...");
        }
    }else{
         alert("您的浏览器不支持 WebSocket!");
    }
}