jquery——九宫格大转盘抽奖实例

 一、用到的图片

二、代码如下，重点是js部分

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>jQuery九宫格大转盘抽奖</title>
<style>
#lottery{width:570px;height:510px;margin:0px auto;border:4px solid #ba1809;}
#lottery table{background-color:yellow;}
#lottery table td{position:relative;width:190px;height:170px;text-align:center;color:#333;font-index:-999}
#lottery table td img{display:block;width:190px;height:170px;}
#lottery table td a{width:190px;height:170px;display:block;text-decoration:none;background:url(images/lottery1.jpg) no-repeat top center;}
#lottery table td a:hover{background-image:url(images/lottery2.jpg);}
#lottery table td.active .mask{display:block;}
.mask{
  width:100%;
  height:100%;
  position:absolute;
  left:0;
  top:0;
  background:url(images/mask.png) no-repeat;
  display:none;
}
</style>
</head>
<body class="keBody">
<!--效果html开始-->
<div id="lottery">
  <table border="0" cellpadding="0" cellspacing="0">
    <tr>
      <td class="lottery-unit lottery-unit-0"><img src="images/gift0.jpg"><div class="mask"></div></td>
      <td class="lottery-unit lottery-unit-1"><img src="images/gift1.jpg"><div class="mask"></div></td>
      <td class="lottery-unit lottery-unit-2"><img src="images/gift2.jpg"><div class="mask"></div></td>
    </tr>
    <tr>
      <td class="lottery-unit lottery-unit-7"><img src="images/gift7.jpg"><div class="mask"></div></td>
      <td><a href="#"></a></td>
      <td class="lottery-unit lottery-unit-3"><img src="images/gift3.jpg"><div class="mask"></div></td>
    </tr>
    <tr>
      <td class="lottery-unit lottery-unit-6"><img src="images/gift6.jpg"><div class="mask"></div></td>
      <td class="lottery-unit lottery-unit-5"><img src="images/gift5.jpg"><div class="mask"></div></td>
      <td class="lottery-unit lottery-unit-4"><img src="images/gift4.jpg"><div class="mask"></div></td>
    </tr>
  </table>
</div>

<script src="http://code.jquery.com/jquery-latest.js"></script>
<script type="text/javascript">
var lottery={
  index:-1,  //当前转动到哪个位置，起点位置
  count:0,  //总共有多少个位置
  timer:0,  //setTimeout的ID，用clearTimeout清除
  speed:20,  //初始转动速度
  times:0,  //转动次数
  cycle:50,  //转动基本次数：即至少需要转动多少次再进入抽奖环节
  prize:-1,  //中奖位置
  init:function(id){
    if ($("#"+id).find(".lottery-unit").length>0) {
      $lottery = $("#"+id);
      $units = $lottery.find(".lottery-unit");
      this.obj = $lottery;
      this.count = $units.length;
      $lottery.find(".lottery-unit-"+this.index).addClass("active");
    };
  },
  roll:function(){
    var index = this.index;
    var count = this.count;
    var lottery = this.obj;
    $(lottery).find(".lottery-unit-"+index).removeClass("active");
    index += 1;
    if (index>count-1) {
      index = 0;
    };
    $(lottery).find(".lottery-unit-"+index).addClass("active");
    this.index=index;
    return false;
  },
  stop:function(index){
    this.prize=index;
    return false;
  }
};

function roll(){
  lottery.times += 1;
  lottery.roll();//转动过程调用的是lottery的roll方法，这里是第一次调用初始化
  if (lottery.times > lottery.cycle+10 && lottery.prize==lottery.index) {
    clearTimeout(lottery.timer);
    lottery.prize=-1;
    lottery.times=0;
    click=false;
  }else{
    if (lottery.times<lottery.cycle) {
      lottery.speed -= 10;
    }else if(lottery.times==lottery.cycle) {
      var index = Math.random()*(lottery.count)|0;
      lottery.prize = index;
    }else{
      if (lottery.times > lottery.cycle+10 && ((lottery.prize==0 && lottery.index==7) || lottery.prize==lottery.index+1)) {
        lottery.speed += 110;
      }else{
        lottery.speed += 20;
      }
    }
    if (lottery.speed<40) {
      lottery.speed=40;
    };
    //console.log(lottery.times+'^^^^^^'+lottery.speed+'^^^^^^^'+lottery.prize);
    lottery.timer = setTimeout(roll,lottery.speed);//循环调用
  }
  return false;
}

var click=false;

window.onload=function(){
  lottery.init('lottery');
  $("#lottery a").click(function(){
    if (click) {//click控制一次抽奖过程中不能重复点击抽奖按钮，后面的点击不响应
      return false;
    }else{
      lottery.speed=100;
      roll();  //转圈过程不响应click事件，会将click置为false
      click=true; //一次抽奖完成后，设置click为true，可继续抽奖
      return false;
    }
  });
};
</script>
<!--效果html结束-->

</body>
</html>

效果如下：

三、注意事项

1、抽奖过程说明

上面只是前端展示的效果。中奖物品通过一个随机数生成。

var index = Math.random()*(lottery.count)|0;

真正开发中中奖物品是通过向后端接口发送请求返回的。

$("#lottery a").click(function(){
       var islogin=checkLogin();
       if(islogin){//已登录用户才能去抽奖
         if (click) {
          return false;
        }else{
          //向后端接口发请求返回中奖结果
          var geturl="http://xxxxxx?username="+username+"&token="+token;
           $.ajax({
           　url:geturl,
            type:"GET",
            dataType:"json",
           async:false,
          success:function(data){
              if(data.errorcode==0){
              var rewardid=data["message"]["rewardid"];
              var cardno=data["message"]["rewardCardNo"];
               var passno=data["message"]["rewardCardPass"];
               var prize=-1;
                var content="";
               if(rewardid=="iphone6"){
               lottery.prize=0;
               prize=0;
              content="一部iphone6手机";
              $("#content1").html(content);
                }else if(rewardid=="PPTVKING"){
                lottery.prize=1;
              prize=1;
               content="一部PPTV KING7s 3D影音手机";
               $("#content1").html(content);
                /*...  */
               }else if(rewardid=="legao"){
              lottery.prize=5;
              prize=5;
              content="一份乐高的玩具";
                $("#content1").html(content);
               }

              lottery.speed=100;
              roll();
              click=true;
              return false;
             }else{
              /*错误处理*/
               if(data.errorcode==3){
              $("#novip").show();
               }else{
              $("#notime").show();
               }
             }
           }/*function结束*/
         });/*ajax结束*/
      }/*else结束*/
      }
});

2、兼容性说明

.mask开始如下，用的是rgba，但是IE8不兼容，改为使用png图片background:url(images/mask.png) no-repeat;

.mask {
  width: 100%;
  height: 100%;
  position: absolute;
  left: 0;
  top: 0;
  background-color: rgba(252,211,4,0.5);
  display: none
}

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