实现秒表功能的核心是使用javascript定时器与dom操作,1. 通过setinterval实现时间更新,2. 利用按钮事件控制开始/暂停和重置,3. 添加圈数按钮记录并显示每次圈时时间,4. 使用css设置字体、布局和按钮样式以美化界面,最终实现一个具备毫秒精度、圈数记录和良好视觉效果的完整秒表功能。

实现秒表功能的核心在于利用JavaScript的定时器和HTML的DOM操作。通过定时器不断更新显示的时间,并通过按钮控制定时器的启动和停止。
解决方案:
首先,你需要一个HTML结构来显示时间,并提供开始/暂停和重置按钮:
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<div id="stopwatch"> <span id="display">00:00:00</span> <button id="startStop">开始</button> <button id="reset">重置</button> </div>
接下来,是JavaScript部分,这部分负责秒表的逻辑:
let timerInterval;
let running = false;
let seconds = 0;
let minutes = 0;
let hours = 0;
function updateDisplay() {
const display = document.getElementById('display');
const formattedSeconds = String(seconds).padStart(2, '0');
const formattedMinutes = String(minutes).padStart(2, '0');
const formattedHours = String(hours).padStart(2, '0');
display.innerText = `${formattedHours}:${formattedMinutes}:${formattedSeconds}`;
}
function startStopwatch() {
if (!running) {
timerInterval = setInterval(() => {
seconds++;
if (seconds === 60) {
seconds = 0;
minutes++;
if (minutes === 60) {
minutes = 0;
hours++;
}
}
updateDisplay();
}, 1000);
running = true;
document.getElementById('startStop').innerText = '暂停';
} else {
clearInterval(timerInterval);
running = false;
document.getElementById('startStop').innerText = '开始';
}
}
function resetStopwatch() {
clearInterval(timerInterval);
running = false;
seconds = 0;
minutes = 0;
hours = 0;
updateDisplay();
document.getElementById('startStop').innerText = '开始';
}
document.getElementById('startStop').addEventListener('click', startStopwatch);
document.getElementById('reset').addEventListener('click', resetStopwatch);
这段代码首先定义了几个变量来跟踪时间状态和定时器。
updateDisplay
startStopwatch
resetStopwatch
要实现毫秒级别的计时,需要修改定时器的间隔和更新逻辑。将
setInterval
let timerInterval;
let running = false;
let milliseconds = 0;
let seconds = 0;
let minutes = 0;
let hours = 0;
function updateDisplay() {
const display = document.getElementById('display');
const formattedMilliseconds = String(milliseconds).padStart(3, '0');
const formattedSeconds = String(seconds).padStart(2, '0');
const formattedMinutes = String(minutes).padStart(2, '0');
const formattedHours = String(hours).padStart(2, '0');
display.innerText = `${formattedHours}:${formattedMinutes}:${formattedSeconds}.${formattedMilliseconds}`;
}
function startStopwatch() {
if (!running) {
timerInterval = setInterval(() => {
milliseconds += 10; // 假设定时器间隔为10ms
if (milliseconds === 1000) {
milliseconds = 0;
seconds++;
if (seconds === 60) {
seconds = 0;
minutes++;
if (minutes === 60) {
minutes = 0;
hours++;
}
}
}
updateDisplay();
}, 10); // 定时器间隔设置为10ms
running = true;
document.getElementById('startStop').innerText = '暂停';
} else {
clearInterval(timerInterval);
running = false;
document.getElementById('startStop').innerText = '开始';
}
}
function resetStopwatch() {
clearInterval(timerInterval);
running = false;
milliseconds = 0;
seconds = 0;
minutes = 0;
hours = 0;
updateDisplay();
document.getElementById('startStop').innerText = '开始';
}
document.getElementById('startStop').addEventListener('click', startStopwatch);
document.getElementById('reset').addEventListener('click', resetStopwatch);这种方法可以提供更高的精度,但需要注意的是,JavaScript的定时器并不是绝对精确的,实际的间隔可能会受到浏览器性能和系统负载的影响。
在秒表运行期间记录圈数,需要在HTML中添加一个“圈数”按钮和一个用于显示圈数的列表。
<div id="stopwatch"> <span id="display">00:00:00</span> <button id="startStop">开始</button> <button id="reset">重置</button> <button id="lap">圈数</button> <ul id="laps"></ul> </div>
然后,修改JavaScript代码,添加一个记录圈数的函数,并在每次点击“圈数”按钮时调用该函数。
let timerInterval;
let running = false;
let seconds = 0;
let minutes = 0;
let hours = 0;
let lapCount = 1;
function updateDisplay() {
const display = document.getElementById('display');
const formattedSeconds = String(seconds).padStart(2, '0');
const formattedMinutes = String(minutes).padStart(2, '0');
const formattedHours = String(hours).padStart(2, '0');
display.innerText = `${formattedHours}:${formattedMinutes}:${formattedSeconds}`;
}
function startStopwatch() {
if (!running) {
timerInterval = setInterval(() => {
seconds++;
if (seconds === 60) {
seconds = 0;
minutes++;
if (minutes === 60) {
minutes = 0;
hours++;
}
}
updateDisplay();
}, 1000);
running = true;
document.getElementById('startStop').innerText = '暂停';
} else {
clearInterval(timerInterval);
running = false;
document.getElementById('startStop').innerText = '开始';
}
}
function resetStopwatch() {
clearInterval(timerInterval);
running = false;
seconds = 0;
minutes = 0;
hours = 0;
updateDisplay();
document.getElementById('startStop').innerText = '开始';
document.getElementById('laps').innerHTML = ''; // 清空圈数列表
lapCount = 1; // 重置圈数计数器
}
function recordLap() {
const lapsList = document.getElementById('laps');
const lapTime = document.getElementById('display').innerText;
const lapItem = document.createElement('li');
lapItem.innerText = `Lap ${lapCount}: ${lapTime}`;
lapsList.appendChild(lapItem);
lapCount++;
}
document.getElementById('startStop').addEventListener('click', startStopwatch);
document.getElementById('reset').addEventListener('click', resetStopwatch);
document.getElementById('lap').addEventListener('click', recordLap);
recordLap
使用CSS可以轻松地美化秒表界面。以下是一些基本的CSS样式示例:
#stopwatch {
font-family: sans-serif;
text-align: center;
padding: 20px;
border: 1px solid #ccc;
width: 300px;
margin: 20px auto;
}
#display {
font-size: 2em;
margin-bottom: 10px;
}
button {
padding: 10px 20px;
margin: 5px;
border: none;
background-color: #007bff;
color: white;
cursor: pointer;
border-radius: 5px;
}
button:hover {
background-color: #0056b3;
}
#laps {
list-style: none;
padding: 0;
}
#laps li {
padding: 5px;
border-bottom: 1px solid #eee;
}这些样式可以设置字体、对齐方式、边框、按钮颜色和列表样式。你可以根据自己的喜好调整这些样式。
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