JavaScript的倒计时附和错误的时间

Question

我想这是我的JavaScript代码能够被读取3小时倒计时，并重定向到倒计时后，一个新的页面完成

<script type="text/javascript"> 
// properties 
var count = 0; 
var counter = null; 

window.onload = function() { 
initCounter(); 
}; 

function initCounter() { 
// get count from localStorage, or set to initial value of 1000 
count = getLocalStorage('count') || 1000; 
counter = setInterval(timer, 1000); //1000 will run it every 1 second 
} 

function setLocalStorage(key, val) { 
if (window.localStorage) { 
    window.localStorage.setItem(key, val); 
} 

return val; 
} 

function getLocalStorage(key) { 
return window.localStorage ? window.localStorage.getItem(key) : ''; 
} 

function timer() { 
count = setLocalStorage('count', count - 1); 
if (count == -1) { 
    clearInterval(counter); 
    return; 
} 

var seconds = count % 60; 
var minutes = Math.floor(count/60); 
var hours = Math.floor(minutes/60); 
minutes %= 60; 
hours %= 60; 

document.getElementById("timer").innerHTML = hours + "hours " + minutes + "minutes and " + seconds + " seconds left to complete this transaction"; // watch for spelling 
} 
</script> 
<div id="timer"></div> 

请帮助我变得更好用使其倒计时到三小时，倒计时完成后又重定向到另一页

Answer 1

您没有正确设置总时间。您将其设置为16分钟而不是3小时。这里是工作的代码（试试JSFiddle）：

var time = 60 * 60 * 3; 
var div = document.getElementById("timer"); 
var t = Date.now(); 

var loop = function(){ 
    var dt = (Date.now() - t) * 1e-3; 

    if(dt > time){ 
    doWhateverHere(); 
    }else{ 
    dt = time - dt; 
    div.innerHTML = `Hours: ${dt/3600 | 0}, Minutes: ${dt/60 % 60 | 0}, Seconds: ${dt % 60 | 0}`; 
    } 

    requestAnimationFrame(loop); 
}; 

loop(); 

另外，不要使用setInterval和setTimeout精确计时。这些功能是不稳定的。改为使用Date.now()。