js随机数组，随机显示3个不重复数字案例：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<script>
//原数组
var arr = [0,1,2,3,4,5,6,7,8,9,10,11];
//输出数组
var out = [];
//输出个数
var num = 3;
while(out.length < num){
var temp = (Math.random()*arr.length) >> 0;
out.push(arr.splice(temp,1));
}
alert(out);
</script>
</body>
</html>