随机数

抽取数组各个值中随机的三个不同的人的名字

var arr = ["王","赵","孙","李","张","周","吴"];
for (var i = 3; i > 0 ; i--) {
    var a = Math.round(Math.random()*arr.length-1);    
        var b = arr.splice(a,1);
        console.log(b);    
}