所以，基本上我试图创建一个简单的 JS 计时器，将在 00:30 开始，一直到 00:00，然后消失。
我已经有 HTML 代码：
<div id="safeTimer">
<h2>Safe Timer</h2>
<p id="safeTimerDisplay">00:30</p>
</div>
现在我知道这将是很容易做到的，如果我做了硬编码的方式：我只是做一个函数，将改变段落的 innerHTML（“00:30”，“00:29”，“00:28”等），然后调用它每秒使用setInterval（）
我将如何做到这一点的简单（不硬编码）的方式？
19
声明此函数并将其绑定到页面的onload事件
function timer(){
var sec = 30;
var timer = setInterval(function(){
document.getElementById('safeTimerDisplay').innerHTML='00:'+sec;
sec--;
if (sec < 0) {
clearInterval(timer);
}
}, 1000);
}
5
请尝试以下代码：
function startTimer(duration, display) {
var timer = duration, minutes, seconds;
setInterval(function () {
minutes = pInt(timer / 60, 10)
seconds = pInt(timer % 60, 10);
minutes = minutes < 10 ? "0" + minutes : minutes;
seconds = seconds < 10 ? "0" + seconds : seconds;
display.textContent = minutes + ":" + seconds;
if (--timer < 0) {
timer = 0;
// timer = duration; // uncomment this line to reset timer automatically after reaching 0
}
}, 1000);
}
window.onload = function () {
var time = 60 / 2, // your time in seconds here
display = document.querySelector('#safeTimerDisplay');
startTimer(time, display);
};
您可以看到一个 Jsfiddle 示例here。
3
请尝试使用下面的代码片段。
<!DOCTYPE html>
<html>
<body>
<div id="safeTimer">
<h2>Safe Timer</h2>
<p id="safeTimerDisplay"></p>
</div>
<script>
var myVar = setInterval(function(){ myTimer() }, 1000);
var secondlimit = 30;
function myTimer() {
if(secondlimit == 0)
{
myStopFunction();
}
document.getElementById("safeTimerDisplay").innerHTML = '00:' + zeroPad(secondlimit,2);
secondlimit = secondlimit - 1;
}
function myStopFunction() {
clearInterval(myVar);
}
function zeroPad(num, places) {
var zero = places - num.toString().length + 1;
return Array(+(zero > 0 && zero)).join("0") + num;
}
</script>
</body>
</html>
0
定时器类
cl Timer {
constructor() {
this.time = 0;
this.element = null;
this.control = true;
this.callback = null;
this.timeLimit = 10;
}
set(time, id, callback = null) {
this.time = time;
this.element = document.getElementById(id);
this.callback = callback;
}
setTimeLimit(time) {
this.timeLimit = time;
}
start(type = 'COUNT_DOWN') {
this.control = true;
setTimeout(() => {
if(type == 'COUNT_DOWN')
this.countDown();
else if(type == 'COUNT_UP')
this.countUp();
}, 1000);
}
format() {
let hours = pInt(this.time / 3600);
let timeLeft = this.time - hours * 3600;
let minutes = pInt(timeLeft / 60);
timeLeft = timeLeft - minutes * 60;
let seconds = timeLeft;
hours = hours.toString();
minutes = minutes.toString();
seconds = seconds.toString();
if (hours.length == 1)
hours = '0' + hours;
if (minutes.length == 1)
minutes = '0' + minutes;
if (seconds.length == 1)
seconds = '0' + seconds;
return hours + ':' + minutes + ':' + seconds;
}
countDown() {
if(!this.control)
return;
let timerblock = this.element;
timerblock.innerHTML = this.format();
timerblock.style.display = 'block';
if (this.time <= 59) {
timerblock.style.color = 'red';
}
if (this.time <= 0) {
timerblock.innerHTML = 'Time end!';
this.callback();
this.stop();
}
else {
setTimeout(() => {
this.countDown();
}, 1000);
this.time--;
}
}
countUp() {
if(!this.control)
return;
let timerblock = this.element;
timerblock.innerHTML = this.format();
timerblock.style.display = 'block';
if(this.time >= this.timeLimit) {
timerblock.innerHTML = 'Timer Limit Exceed!';
this.callback();
this.stop();
}
else {
setTimeout(() => {
this.countUp();
}, 1000);
this.time++;
}
}
stop() {
this.control = false;
}
}
创建一个 div set 属性 id = 'timer'
<div id="timer"></div>
COUNT_DOWN 计时器中的 time = =0
超过 COUNT_UP 计时器中的时间限制
const callback = () => {
console.log('callback function called from timer');
}
创建计时器实例
const timer = new Timer();
set 方法接受 3 个参数
时间
dom 元素 id
回调函数
timer.set(10, 'timer', callback);
最后调用 start 函数启动定时器
它需要一个字符串 'COUNT_DOWN' 或 'COUNT_UP' 默认情况下它是 'COUNT_DOWN'
timer.start('COUNT_DOWN');
停止计时器
timer.stop();
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