简单易扩展可控性强的Jquery转盘抽奖程序

<script type="text/javascript">
var index = 1,  //当前亮区位置
prevIndex = 14,  //前一位置
Speed = 300,  //初始速度
Time,   //计时器
arr_length = 14,  //奖池奖品数量
EndIndex = 1,  //决定在哪一格变慢
cycle = 0,   //计算圈数  
EndCycle = 3,  //转动多少圈后停下
flag = false,  //结束转动标志
random_num = 1,  //中奖的格子
quick = 0;   //多少格后开始加速
function StartGame(){
 $("#random_box li").removeClass("random_current");
 //产出随机中奖数1--14之间
 //在实际应用中，中奖数应通过Ajax从后台获得，以确保中奖概率的可控性
 random_num = Math.floor(Math.random() * 14 + 1);
 //从第一格开始转动
 index = 1;
 //圈数计数器置0
 cycle = 0;
 flag = false;
 //中奖格子前5格开始变慢
 if(random_num > 10) {
  EndIndex = random_num - 10; 
 } else {
  EndIndex = random_num + arr_length - 10;
 }
 Time = setInterval(Star,Speed);
}
function Star(num){
  //跑马灯变速
  if(flag == false){
 //走五格开始加速
 if(quick == 5){
  clearInterval(Time);
  Speed=50;
  Time=setInterval(Star,Speed);
 }
 //跑指定圈数后开始减速
 if(cycle == EndCycle + 1 && index - 1 == EndIndex){
  clearInterval(Time);
  Speed = 300;
  //触发结束
  flag = true;
  Time = setInterval(Star,Speed);
 }
 }
  if(index > arr_length){
    index = 1;
    cycle ++;
  }
  //结束转动并选中号码
  if(flag == true && index==parseInt(random_num)){ 
 quick = 0;
 clearInterval(Time);
  }
  //设置当前选中样式
  $("#random_"+index).addClass('random_current'); 
  if(index > 1)
    prevIndex = index - 1;
  else{
    prevIndex = arr_length;
  }
  //取消上次选择样式 
  $("#random_"+prevIndex).removeClass('random_current'); 
  index ++;
  quick ++;
}
</script>

<div class="box">
 <div class="inbox">
 <ul id="random_box">
  <li id="random_1"><img src="images/img01.gif"></li>
  <li id="random_2"><img src="images/img02.gif"></li>
  <li id="random_3"><img src="images/ts.gif"></li>
  <li id="random_4"><img src="images/img03.gif"></li>
  <li id="random_5"><img src="images/img04.gif"></li>
  <li id="random_6"><img src="images/ts.gif"></li>
  <li id="random_7"><img src="images/img05.gif"></li>
  <li id="random_8"><img src="images/img06.gif"></li>
  <li id="random_9"><img src="images/img07.gif"></li>
  <li id="random_10"><img src="images/ts.gif"></li>
  <li id="random_11"><img src="images/img01.gif"></li>
  <li id="random_12"><img src="images/img02.gif"></li>
  <li id="random_13"><img src="images/ts.gif"></li>
  <li id="random_14"><img src="images/img04.gif"></li> 
 </ul>
 <b class="ok" onclick="StartGame()">我要抽奖</b>
 </div>
</div>

/* 
 CSS Document
 Power by www.jb51.net
*/
body,p,ul,ol,li,img,div{margin:0;padding:0;border:0;}
ul,li{list-style:none;}
body{font-size:12px;font-family:Arial, Helvetica, sans-serif; text-align:center; margin:0 auto;}
.box{ padding:9px 0 0 11px; width:759px; height:611px; background:#ccc; margin:20px auto; }
.inbox{ width:751px; height:596px;position:relative;}
#random_box li{ position:absolute; width:144px; overflow:hidden; height:144px; border:1px solid #c7c5ca; background:#fff;}
#random_box li img{ width:144px; display:block; height:144px;}
.ok{ display:block; width:442px; height:294px; background:#c00; color:#fff; font-size:48px; position:absolute; 
top:149px; left:148px; cursor:pointer; text-align:center; line-height:280px;}
#random_1{ left:0; top:0;}
#random_2{ left:148px;top:0;}
#random_3{ left:296px;top:0;}
#random_4{ left:444px;top:0;}
#random_5{ left:592px;top:0; }
#random_6{ left:592px;top:148px;}
#random_7{ left:592px; top:298px;}
#random_8{ left:592px; top:446px;}
#random_9{ left:444px; top:446px;}
#random_10{ left:296px; top:446px;}
#random_11{ left:148px; top:446px;}
#random_12{ left:0; top:446px;}
#random_13{ left:0; top:298px;}
#random_14{ left:0; top:148px;}
#random_box li.random_current{border:2px solid red;}