在IE中进行轮询的setTimeout间隔是多少? [英] What is a good setTimeout interval for polling in a IE?

问题描述

我有一个在浏览器(IE)中运行的ActiveX对象(具有我的源代码). ActiveX对象具有一个UI，该UI引发事件.我想在浏览器中响应这些事件.

I have an ActiveX object (who source code I have) running in a browser (IE). The ActiveX object has a UI, which raises events. I want to respond to those events in the browser.

我不想从ActiveX对象事件中调用JavaScript函数:因此，我希望JavaScript轮询ActiveX对象的方法(例如，您要报告任何事件吗?")

I don't want to invoke JavaScript functions from the ActiveX object events: and therefore, instead, I want the JavaScript to poll a method of the ActiveX object (to say, "do you have any events to report?").

我将使用以下代码来做到这一点:

I'll do that with code like this:

function findActiveXObject() {
    return document.getElementById('MyActiveXObject');
}
function startPolling() {
    setTimeout('pollForEvents()', 100);
}
function pollForEvents() {
    var activeXObject = findActiveXObject();
    var eventMsg = activeXObject.PollForEvent();
    if (eventMsg != null)
    {
        //do something with the event
        alert(eventMsg);
    }
    //poll again soon
    startPolling();
}

什么是好的轮询间隔?

我猜，尽管我不确定，但是工作量很小:它只是在调用ActiveX对象的方法，该方法要么返回已经缓存的字符串，要么返回null.

I guess, though I'm not sure, that the amount of work is small: it's just calling a method of an ActiveX object, which either returns an already cached string or returns null.

我想经常轮询:这样看起来浏览器(实际上是JavaScript)会迅速响应ActiveX对象中的UI事件.

I'd like to poll frequently: so that it looks like the browser (actually the JavaScript) responds promptly to UI events in the ActiveX object.

100毫秒太小了吗? 50毫秒怎么样?

Is 100 msec too small? How about 50 msec?

在100毫秒的间隔内，我在浏览器中仅看到1％的CPU利用率:但这只是在我的机器上.一般情况下(运行IE的台式机)如何?

With a 100 msec interval I see only a 1% CPU utilization in the browser: but that's just on my machine. What about in general (desktop mchines running IE)?

如果这是本机线程，我不必担心每50毫秒将其唤醒一次，但是我几乎没有在IE中运行JavaScript的经验.

If this were a native thread I wouldn't worry about waking it up every 50 msec, but I have little experience with running JavaScript in IE.

推荐答案

我建议每秒轮询一次.
您真的需要即时反应吗?

I would recommend polling once every second.
Do you really need instantaneous reactions?

此外，您不应将字符串传递给setTimeout.
相反，您应该像htis这样传递函数本身:

Also, you shouldn't pass a string to setTimeout.
Instead, you should pass the function itself, like htis:

setTimeout(pollForEvents, 1000);

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