Chrome（和其他浏览器）如何处理ASETSETIMEOUT＆＃x201D;当隐藏浏览器选项卡被隐藏和不活动时，设置为高于1000毫秒？

发布于 2025-01-22 11:58:37 字数 1216 浏览 0 评论 0原文

我正在通过外部供应商为客户保留的网站上调试一些登录/注销问题，并希望标题可以解释内容，但更多详细信息如下。

据我了解，在Chrome中隐藏的选项卡中运行的任何JavaScript都会改变任何settimeout的值，以保持1000毫秒，以保持整体系统性能而不是浪费资源。如在此站点上说明了：

“浏览器就是这样做的。对于无活动的选项卡，无论代码中指定的原始延迟如何，它们都会自动防风计时器每1秒运行一次。 例如，如果代码最初使用的setInterval（）每50 ms运行一些代码，一旦将应用程序移至背景选项卡，则该间隔会自动变为1000 ms（1秒）。”

对于settimeout值，该值的设置低于1,000毫秒（例如50毫秒等），这绝对是有道理的。但是，值高于1,000毫秒呢？

Chrome是否将settimeout值设置为1,000毫秒，即使900,000毫秒（又名：900秒，又名：15分钟）显然高于此？

这是供应商网页中的一部分代码，我认为正在引起我试图协助调试的问题。当它在隐藏的选项卡中时，它没有完成工作。

function keepSessionAlive() {
    if (externalAdminWindow && externalAdminWindow.closed) {
        externalAdminWindow = null;
    }
    if (externalFGWindow && externalFGWindow.closed) {
        externalFGWindow = null;
    }
    if (externalAdminWindow || externalFGWindow) {
        $find("ctl00_RadAjaxManager1").ajaxRequest("KeepAlive");
        setTimeout(function() {
            keepSessionAlive();
        }, 900000);
    }
}

原文

I’m debugging some login/logout issues on a site maintained by an outside vendor for a client and hopefully the title explains things, but more details are below.

As I understand it, any JavaScript running in a hidden tab in Chrome will alter the value of any setTimeout to be 1000 milliseconds to maintain overall system performance and not waste resources. As explained on this site:

“Browsers do exactly this. For inactive tabs, they automatically throttle timers to run every 1 second, regardless of the original delay specified in the code. For example, if the code originally used setInterval() to run some code every 50 ms, once the application is moved to a background tab, the interval automatically becomes 1000 ms (1 second).”

That definitely makes sense in the case of a setTimeout value that is set lower than 1,000 milliseconds like 50 milliseconds and such. But what about values higher than 1,000 milliseconds?

Will Chrome set the setTimeout value to 1,000 milliseconds even though 900,000 milliseconds (aka: 900 seconds, aka: 15 minutes) is clearly higher than that?

Here is a chunk of code from the vendor’s web page I believe is causing issues I am attempting to assist in debugging. It doesn’t do its job when it is in a hidden tab.

function keepSessionAlive() {
    if (externalAdminWindow && externalAdminWindow.closed) {
        externalAdminWindow = null;
    }
    if (externalFGWindow && externalFGWindow.closed) {
        externalFGWindow = null;
    }
    if (externalAdminWindow || externalFGWindow) {
        $find("ctl00_RadAjaxManager1").ajaxRequest("KeepAlive");
        setTimeout(function() {
            keepSessionAlive();
        }, 900000);
    }
}

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