核心：js的Math對象和Array對象
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>random</title>
<style>
#awardListDom{width: 100%;}
</style>
</head>
<body>
<label for="awardListDom">獎項列表</label><br>
<input type="text" value="" id="awardListDom"> <br>
<label for="num">抽到的獎</label><br>
<input type="text" value="" id="num"> <br>
<button id="submit">開始抽獎</button>
<script>
/*
* 思路：隨機抽獎，抽一個獎項便減少一個
* Math 對象方法：http://www.w3school.com.cn/jsref/jsref_obj_math.asp
* -random():返回 0 ~ 1 之間的隨機數。
* -floor():獲取整數
* 數組操作：
* - splice(x,y); x:起始位置， y:獲取並刪除個數
*/
function random(min,max){
return Math.floor(min+Math.random()*(max-min));
}
var awardListDom=document.getElementById("awardListDom"),
num=document.getElementById("num"),
submit=document.getElementById("submit");
var awardList=["一等獎","二等獎","二等獎","三等獎","三等獎","三等獎","鼓勵獎","鼓勵獎","鼓勵獎","鼓勵獎","謝謝參與","謝謝參與","謝謝參與","謝謝參與","謝謝參與","謝謝參與"];
awardListDom.value=awardList;
submit.onclick=function(){
//引用數組
var oldArray=awardList;
var rNum=random(0,oldArray.length);
if(oldArray.length<1){
awardListDom.value="活動結束";
num.value="活動結束";
}
else{
num.value=oldArray[rNum];
oldArray.splice(rNum,1);
awardListDom.value=oldArray;
}
}
</script>
</body>
</html>
demo:http://demo.jb51.net/js/2015/choujiang/
github:https://github.com/litengdesign/award