핵심: js Math 객체와 Array 객체
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>random</title>
<style>
#awardListDom{width: 100%;}
</style>
</head>
<body>
<label for="awardListDom">奖项列表</label><br>
<input type="text" value="" id="awardListDom"> <br>
<label for="num">抽到的奖</label><br>
<input type="text" value="" id="num"> <br>
<button id="submit">开始抽奖</button>
<script>
/*
* 思路：随机抽奖，抽一个奖项便减少一个
* Math 对象方法：http://www.w3school.com.cn/jsref/jsref_obj_math.asp
* -random():返回 0 ~ 1 之间的随机数。
* -floor():获取整数
* 数组操作：
* - splice(x,y); x:起始位置， y:获取并删除个数
*/
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=["一等奖","二等奖","二等奖","三等奖","三等奖","三等奖","鼓励奖","鼓励奖","鼓励奖","鼓励奖","谢谢参与","谢谢参与","谢谢参与","谢谢参与","谢谢参与","谢谢参与"];
awardListDom.value=awardList;
submit.onclick=function(){
//引用数组
var oldArray=awardList;
var rNum=random(0,oldArray.length);
if(oldArray.length<1){
awardListDom.value="活动结束";
num.value="活动结束";
}
else{
num.value=oldArray[rNum];
oldArray.splice(rNum,1);
awardListDom.value=oldArray;
}
}
</script>
</body>
</html>
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