我是Java语言的新手，现在正在尝试倒数计时器。每次完成倒数计时时，页面弹出警报框都会显示：倒数结束。但是每次我单击“确定”时，警报框都不会关闭。我认为它与windows.onload函数有关，但是我不知道如何解决它。
function startTimer(duration, display) {
var timer = duration,
minutes,
seconds;
setInterval(function() {
minutes = parseInt(timer / 60, 10);
seconds = parseInt(timer % 60, 10);
minutes = minutes < 10 ? '0' + minutes : minutes;
seconds = seconds < 10 ? '0' + seconds : seconds;
display.textContent = minutes + ':' + seconds;
if (--timer < 0) {
timer = 0;
alert('countdown finished');
document.getElementById('demo').innerHTML = 'EXPIRED';
}
}, 1000);
}
window.onload = function() {
var fiveMinutes = 60 * 0.1,
//display = document.querySelector('#time');
display = document.getElementById('demo');
startTimer(fiveMinutes, display);
};<h1>conutdown</h1>
<p id="demo"></p>
<!-- <div>Registration closes in <span id="time">05:00</span> minutes!</div> -->最佳答案
您必须使用clearInterval()清除间隔
<html lang="en">
<head>
<meta charset="UTF-8" />
<title>countdown</title>
</head>
<body>
<h1>conutdown</h1>
<p id="demo"></p>
<!-- <div>Registration closes in <span id="time">05:00</span> minutes!</div> -->
<script>
function startTimer(duration, display) {
var timer = duration,
minutes,
seconds;
var intrvl = setInterval(function() {
minutes = parseInt(timer / 60, 10);
seconds = parseInt(timer % 60, 10);
minutes = minutes < 10 ? '0' + minutes : minutes;
seconds = seconds < 10 ? '0' + seconds : seconds;
display.textContent = minutes + ':' + seconds;
if (--timer < 0) {
timer = 0;
alert('countdown finished');
document.getElementById('demo').innerHTML = 'EXPIRED';
clearInterval(intrvl); // Clears interval
}
}, 1000);
}
window.onload = function() {
var fiveMinutes = 60 * 0.1,
//display = document.querySelector('#time');
display = document.getElementById('demo');
startTimer(fiveMinutes, display);
};
</script>
</body>
</html>关于javascript - 警报框javascript无法关闭，因为window.onload，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/58317347/