核心:js的Math对象和Array对象
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<!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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github:https://github.com/litengdesign/award