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js实现转盘抽奖

2026-01-30 11:06:38JavaScript

实现思路

使用HTML、CSS和JavaScript创建一个转盘抽奖功能。核心是通过CSS动画实现转盘旋转，JavaScript控制旋转时间和停止位置。

HTML结构

<div class="wheel-container">
  <div class="wheel"></div>
  <button id="spin-btn">开始抽奖</button>
</div>

CSS样式

.wheel-container {
  position: relative;
  width: 300px;
  height: 300px;
  margin: 0 auto;
}

.wheel {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  position: relative;
  overflow: hidden;
  transition: transform 4s cubic-bezier(0.17, 0.67, 0.12, 0.99);
  transform: rotate(0deg);
}

/* 添加奖品扇形区域 */
.wheel::before {
  content: '';
  position: absolute;
  width: 50%;
  height: 50%;
  background: conic-gradient(
    #ff0000 0deg 60deg,
    #00ff00 60deg 120deg,
    #0000ff 120deg 180deg,
    #ffff00 180deg 240deg,
    #ff00ff 240deg 300deg,
    #00ffff 300deg 360deg
  );
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  margin: auto;
  border-radius: 50%;
}

#spin-btn {
  display: block;
  margin: 20px auto;
  padding: 10px 20px;
  background: #4CAF50;
  color: white;
  border: none;
  border-radius: 5px;
  cursor: pointer;
}

JavaScript逻辑

const wheel = document.querySelector('.wheel');
const spinBtn = document.getElementById('spin-btn');
let canSpin = true;

// 奖品配置
const prizes = ['一等奖', '二等奖', '三等奖', '四等奖', '五等奖', '六等奖'];
const prizeAngles = [30, 90, 150, 210, 270, 330]; // 每个奖品的中心角度

spinBtn.addEventListener('click', () => {
  if (!canSpin) return;

  canSpin = false;
  const randomIndex = Math.floor(Math.random() * prizes.length);
  const targetAngle = 360 * 5 + prizeAngles[randomIndex]; // 旋转5圈后停在目标位置

  wheel.style.transform = `rotate(${-targetAngle}deg)`;

  setTimeout(() => {
    alert(`恭喜获得: ${prizes[randomIndex]}`);
    canSpin = true;
  }, 4000);
});

实现说明

使用CSS的conic-gradient创建彩色扇形转盘
通过transform和transition实现平滑旋转动画
计算随机停止位置时添加多圈旋转效果
使用标志位防止重复点击
旋转结束后显示中奖信息

扩展功能

如果需要更精确控制，可以改用requestAnimationFrame实现动画：

let startTime;
let startAngle = 0;
const duration = 4000; // 动画持续时间

function spinWheel(targetAngle) {
  startTime = null;
  startAngle = 0;

  function animate(timestamp) {
    if (!startTime) startTime = timestamp;
    const progress = Math.min((timestamp - startTime) / duration, 1);
    const currentAngle = easeOut(progress) * targetAngle;

    wheel.style.transform = `rotate(${-currentAngle}deg)`;

    if (progress < 1) {
      requestAnimationFrame(animate);
    } else {
      const prizeIndex = Math.floor(((targetAngle % 360) / 360) * prizes.length);
      alert(`恭喜获得: ${prizes[prizeIndex]}`);
      canSpin = true;
    }
  }

  requestAnimationFrame(animate);
}

function easeOut(t) {
  return 1 - Math.pow(1 - t, 3);
}