用JS简单实现九宫格抽奖的示例代码

const total_items = 8 //奖品的总数
let prizeId = -1 // 奖品的结果，初始值为-1，表示还没有开始抽奖
let current_index = -1 //当前选中奖项索引
const minimum_jumps = 30 // 超过该数字进入抽奖
let jumps = 0 //抽奖转动次数，初始值为0
let speed = 100  //转动速度
let timer = 0   
let disabled = false
// 奖品抽奖
function controll() {
  jumps += 1
  runCircle()
  // 抽到奖品停止游戏
  if (jumps > minimum_jumps + 10 && prizeId === current_index) {
    clearTimeout(timer)
    disabled = false
    const message = document.createElement('p')
    message.className = 'message'
    message.innerHTML = `恭喜你获得：${prize_list[current_index].name}!`
    container.appendChild(message)
    prizeId = -1
    jumps = 0
  } else {
      // 加快
    if (jumps < minimum_jumps) {
      speed -= 5
      // 決定奖品的位置
    } else if (jumps === minimum_jumps) {
      prizeId = generatePrizeNumber()
    } else {
      // 下一个就是奖品时放慢速度
      if ((jumps > minimum_jumps + 10) && prizeId === (current_index + 1)) {
        speed += 600
      } else {
        speed += 20 // 減速
      }
    }
    if (speed < 40) {
      speed = 40
    }
    timer = setTimeout(controll, speed)
  }
}
function init() {
  jumps = 0
  speed = 100
  prizeId = -1
  controll()
}