是否有可能在JavaScript中检测“空闲”时间?
我的主要用例可能是预取或预加载内容。
我将空闲时间定义为用户不活动或没有任何CPU使用的时间段
当前回答
(部分灵感来自Equiman回答的良好核心逻辑。)
sessionExpiration.js
sessionExpiration.js是轻量级的，但有效和可定制的。一旦实现，只在一行中使用:
sessionExpiration(idleMinutes, warningMinutes, logoutUrl);
Affects all tabs of the browser, not just one. Written in pure JavaScript, with no dependencies. Fully client side. (If so wanted.) Has warning banner and countdown clock, that is cancelled by user interaction. Simply include the sessionExpiration.js, and call the function, with arguments [1] number of idle minutes (across all tabs) until user is logged out, [2] number of idle minutes until warning and countdown is displayed, and [3] logout url. Put the CSS in your stylesheet. Customize it if you like. (Or skip and delete banner if you don't want it.) If you do want the warning banner however, then you must put an empty div with ID sessExpirDiv on your page (a suggestion is putting it in the footer). Now the user will be logged out automatically if all tabs have been inactive for the given duration. Optional: You may provide a fourth argument (URL serverRefresh) to the function, so that a server side session timer is also refreshed when you interact with the page.
这是一个例子，如果你不改变CSS，它看起来是什么样子的。
其他回答
我终于把这个工作在我的网站。我发现equiman的回答最有帮助。这个答案的问题是JavaScript中的alert()函数会暂停脚本执行。如果您像我一样希望发送一个警报，然后如果没有收到响应，站点将自动注销，那么暂停执行是一个问题。
解决方案是用自定义除法替换alert()，如下所述。
下面是代码:(注意:您需要更改第58行以重定向到您的站点的适当URL)
var inactivityTracker = function () { // Create an alert division var alertDiv = document.createElement("div"); alertDiv.setAttribute("style","position: absolute;top: 30%;left: 42.5%;width: 200px;height: 37px;background-color: red;text-align: center; color:white"); alertDiv.innerHTML = "You will be logged out in 5 seconds!!"; // Initialise a variable to store an alert and logout timer var alertTimer; var logoutTimer; // Set the timer thresholds in seconds var alertThreshold = 3; var logoutThreshold = 5; // Start the timer window.onload = resetAlertTimer; // Ensure timer resets when activity logged registerActivityLoggers(resetAlertTimer); // ***** FUNCTIONS ***** // // Function to register activities for alerts function registerActivityLoggers(functionToCall) { document.onmousemove = functionToCall; document.onkeypress = functionToCall; } // Function to reset the alert timer function resetAlertTimer() { clearTimeout(alertTimer); alertTimer = setTimeout(sendAlert, alertThreshold * 1000); } // Function to start logout timer function startLogoutTimer() { clearTimeout(logoutTimer); logoutTimer = setTimeout(logout, logoutThreshold * 1000); } // Function to logout function sendAlert() { // Send a logout alert document.body.appendChild(alertDiv); // Start the logout timer startLogoutTimer(); // Reset everything if an activity is logged registerActivityLoggers(reset); } // Function to logout function logout(){ //location.href = 'index.php'; } // Function to remove alert and reset logout timer function reset(){ // Remove alert division alertDiv.parentNode.removeChild(alertDiv); // Clear the logout timer clearTimeout(logoutTimer); // Restart the alert timer document.onmousemove = resetAlertTimer; document.onkeypress = resetAlertTimer; } }; <html> <script type="text/javascript" src="js/inactivityAlert.js"></script> <head> <title>Testing an inactivity timer</title> </head> <body onload="inactivityTracker();" > Testing an inactivity timer </body> </html>
下面是tvanfosson的想法的粗略jQuery实现:
$(document).ready(function(){
idleTime = 0;
//Increment the idle time counter every second.
var idleInterval = setInterval(timerIncrement, 1000);
function timerIncrement()
{
idleTime++;
if (idleTime > 2)
{
doPreload();
}
}
//Zero the idle timer on mouse movement.
$(this).mousemove(function(e){
idleTime = 0;
});
function doPreload()
{
//Preload images, etc.
}
})
你肯定想知道window.requestIdleCallback()，它在浏览器空闲期间对要调用的函数进行排队。
您可以在Quicklink repo中看到这个API的优雅用法。
const requestIdleCallback = window.requestIdleCallback ||
function (cb) {
const start = Date.now();
return setTimeout(function () {
cb({
didTimeout: false,
timeRemaining: function () {
return Math.max(0, 50 - (Date.now() - start));
},
});
}, 1);
};
上面代码的意思是:如果浏览器支持requestIdleCallback(检查兼容性)，就使用它。如果不支持，则使用setTimeout(()=>{}， 1)作为回退，它应该在事件循环结束时将被调用的函数排队。
然后你可以这样使用它:
requestIdleCallback(() => {...}, {
timeout: 2000
});
第二个参数是可选的，如果希望确保函数执行，则可能需要设置一个超时。
您可能可以通过检测窗体主体上的鼠标移动并使用最后的移动时间更新全局变量来拼凑一些东西。然后，您需要运行一个间隔计时器，定期检查最后一次移动时间，如果距离检测到最后一次鼠标移动已经足够长，则执行一些操作。
就像它可以得到的那样简单，检测鼠标移动的时间:
var idle = false;
document.querySelector('body').addEventListener('mousemove', function(e) {
if(idle!=false)
idle = false;
});
var idleI = setInterval(function()
{
if(idle == 'inactive')
{
return;
}
if(idle == true)
{
idleFunction();
idle = 'inactive';
return;
}
idle = true;
}, 30000); // half the expected time. Idle will trigger after 60 s in this case.
function idleFuntion()
{
console.log('user is idle');
}
