html5之Web Workers示例

     Web Workers使得html5也可以使用类似后台异步化、线程化的操作,让假死、卡不再存在,非常适合httpreqeust/io等操作。示例如下:

x.htm

<html>
<head>
<title>Web Workers</title>
</head>
<body>
<div class="page">
 <div class="article">
  <h2 class="topic"><strong id="result">正在计算Fibonacci(35)...,你可以先看看下面的介绍!</strong></h2>
 </div>
</div>
</body>
<script type="text/javascript">
var wt = function(){
    if(typeof Worker == 'undefined'){document.getElementById('result').innerHTML = '你正在使用的浏览器暂时还不支持WEB Workers!';return;}
    var worker = new Worker("x.js");
    worker.onmessage = function(event){
        document.getElementById('result').innerHTML = event.data;
    };
    worker.onerror = function(event){
        alert('Worker error:'+error.message+'\n');
        throw error;
    };
    worker.postMessage('35');
};
wt();
</script>
</html>

x.js:

var fibonacci = function(n){
    var rv = {'0':0,'1':1},l=0,r=0,i=0;
    !function(n){
        if(!(n in rv)){
            l = rv[(n-1)]||arguments.callee(n-1);
            r = rv[(n-2)]||arguments.callee(n-2);
            rv[n] = l+r;
        }
        return rv[n];
    }(n);
    l = r = null;
    return rv[n];
};

var fibonacci2 = function(n){
    var i2 = 0;
    var fb2 = function(n){
        return n<2?n:arguments.callee(n-1)+arguments.callee(n-2);
    };
    return fb2(n);
};

var onmessage = function(event){
    var n = parseInt(event.data,10);
    postMessage(fibonacci2(n));
};

posted on 2011-05-16 11:40  chuncn  阅读(773)  评论(0编辑  收藏  举报

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