js 实现秒表

2026-03-15 03:24:13JavaScript

js 实现秒表

实现秒表功能

使用JavaScript实现秒表功能需要记录开始时间、暂停时间以及计算经过的时间。以下是一个完整的实现方案：

HTML结构

<div id="stopwatch">
  <div id="display">00:00:00</div>
  <button id="startBtn">Start</button>
  <button id="pauseBtn" disabled>Pause</button>
  <button id="resetBtn" disabled>Reset</button>
</div>

CSS样式

#stopwatch {
  font-family: Arial, sans-serif;
  text-align: center;
  margin: 50px auto;
  width: 300px;
}

#display {
  font-size: 48px;
  margin-bottom: 20px;
}

button {
  padding: 10px 20px;
  margin: 0 5px;
  font-size: 16px;
  cursor: pointer;
}

JavaScript实现

class Stopwatch {
  constructor(display, startBtn, pauseBtn, resetBtn) {
    this.display = display;
    this.startBtn = startBtn;
    this.pauseBtn = pauseBtn;
    this.resetBtn = resetBtn;
    this.running = false;
    this.startTime = 0;
    this.elapsedTime = 0;
    this.timer = null;

    this.startBtn.addEventListener('click', () => this.start());
    this.pauseBtn.addEventListener('click', () => this.pause());
    this.resetBtn.addEventListener('click', () => this.reset());
  }

  start() {
    if (!this.running) {
      this.startTime = Date.now() - this.elapsedTime;
      this.timer = setInterval(() => this.update(), 10);
      this.running = true;
      this.startBtn.disabled = true;
      this.pauseBtn.disabled = false;
      this.resetBtn.disabled = false;
    }
  }

  pause() {
    if (this.running) {
      clearInterval(this.timer);
      this.elapsedTime = Date.now() - this.startTime;
      this.running = false;
      this.startBtn.disabled = false;
      this.pauseBtn.disabled = true;
    }
  }

  reset() {
    clearInterval(this.timer);
    this.running = false;
    this.elapsedTime = 0;
    this.display.textContent = '00:00:00';
    this.startBtn.disabled = false;
    this.pauseBtn.disabled = true;
    this.resetBtn.disabled = true;
  }

  update() {
    const elapsed = Date.now() - this.startTime;
    const hours = Math.floor(elapsed / 3600000);
    const minutes = Math.floor((elapsed % 3600000) / 60000);
    const seconds = Math.floor((elapsed % 60000) / 1000);
    const milliseconds = Math.floor((elapsed % 1000) / 10);

    this.display.textContent = 
      `${hours.toString().padStart(2, '0')}:${minutes.toString().padStart(2, '0')}:${seconds.toString().padStart(2, '0')}.${milliseconds.toString().padStart(2, '0')}`;
  }
}

// 初始化秒表
const display = document.getElementById('display');
const startBtn = document.getElementById('startBtn');
const pauseBtn = document.getElementById('pauseBtn');
const resetBtn = document.getElementById('resetBtn');

const stopwatch = new Stopwatch(display, startBtn, pauseBtn, resetBtn);