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js实现抽奖效果

2026-01-30 13:36:02JavaScript

实现抽奖效果的方法

基础抽奖逻辑

使用Math.random()生成随机数，结合数组索引实现抽奖效果。以下是一个简单的实现示例：

const prizes = ['一等奖', '二等奖', '三等奖', '谢谢参与'];
const result = prizes[Math.floor(Math.random() * prizes.length)];
console.log('抽奖结果:', result);

动画效果增强

添加旋转动画效果，模拟真实抽奖转盘行为：

function startLottery() {
  const element = document.getElementById('prize-wheel');
  let rotations = 0;
  const totalRotations = 5 + Math.floor(Math.random() * 3);

  const spinInterval = setInterval(() => {
    rotations += 0.1;
    element.style.transform = `rotate(${rotations * 360}deg)`;

    if(rotations >= totalRotations) {
      clearInterval(spinInterval);
      determineWinner();
    }
  }, 50);
}

概率控制

为不同奖项设置不同概率，使用权重系统：

const prizePool = [
  { name: '特等奖', weight: 1 },
  { name: '一等奖', weight: 5 },
  { name: '二等奖', weight: 15 },
  { name: '三等奖', weight: 30 },
  { name: '参与奖', weight: 50 }
];

function getRandomPrize() {
  const totalWeight = prizePool.reduce((sum, p) => sum + p.weight, 0);
  let random = Math.random() * totalWeight;

  for(const prize of prizePool) {
    if(random < prize.weight) {
      return prize.name;
    }
    random -= prize.weight;
  }
}

完整组件实现

结合HTML和CSS创建完整的抽奖组件：

<div class="lottery-container">
  <div id="prize-wheel" class="wheel"></div>
  <button onclick="startLottery()">开始抽奖</button>
  <div id="result-display"></div>
</div>

<style>
.wheel {
  width: 300px;
  height: 300px;
  border-radius: 50%;
  background: conic-gradient(
    red 0% 10%,
    blue 10% 30%,
    green 30% 60%,
    yellow 60% 100%
  );
  transition: transform 3s cubic-bezier(0.17, 0.67, 0.21, 0.99);
}
</style>

<script>
// 这里放置抽奖逻辑代码
</script>

性能优化技巧

避免频繁DOM操作，使用requestAnimationFrame优化动画：

function animateSpin(timestamp) {
  if(!startTime) startTime = timestamp;
  const progress = (timestamp - startTime) / duration;

  if(progress < 1) {
    const rotation = easeOut(progress) * 360 * spinCount;
    wheelElement.style.transform = `rotate(${rotation}deg)`;
    requestAnimationFrame(animateSpin);
  } else {
    showResult();
  }
}

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