我有一个脚本可以直接运行,也可以在浏览器中作为 Web Worker 运行。我只想在作为 worker 运行时运行此脚本的一部分;所以我的问题是,脚本如何将自己标识为以这种方式运行?
我在规范中看不到任何允许这种情况发生的内容;我是否遗漏了一些明显的东西?
最佳答案
在以下内容中:
<html>
<head>
<title>Worker</title>
</head>
<body>
</body>
<script >
var w = new Worker ('worker.js');
w.onmessage = function (e) {
document.body.innerHTML += '<br>' + 'WORKER : ' + e.data;
};
</script>
<script src='worker.js'></script>
</html>
worker.js 作为脚本和 worker 被调用。
worker.js 包含:
var msg = 'postMessage is ' + postMessage.toString () +
', self.constructor is ' + self.constructor;
try {
postMessage (msg);
} catch (e) {
document.body.innerHTML += '<br>SCRIPT : ' + msg;
}
在 worker 环境中,postMessage 成功,在脚本环境中失败,因为它未定义,或者在浏览器中,它需要第二个参数。
输出是:
Chrome :
SCRIPT : postMessage is function () { [native code] }, self.constructor is function DOMWindow() { [native code] }
WORKER : postMessage is function postMessage() { [native code] }, self.constructor is function DedicatedWorkerContext() { [native code] }
火狐浏览器:
SCRIPT : postMessage is function postMessage() { [native code] }, self.constructor is [object Window]
WORKER : postMessage is function postMessage() { [native code] }, self.constructor is function DedicatedWorkerGlobalScope() { [native code] }
歌剧:
WORKER : postMessage is function postMessage() { [native code] }, self.constructor is function Object() { [native code] }
SCRIPT : postMessage is function postMessage() { [native code] }, self.constructor is function Object() { [native code] }
全部在 Ubuntu 下。
关于javascript - 识别 JS 脚本何时作为 Worker 运行,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/8523121/