如何用 JavaScript 实现一个随机抽奖系统，并根据号码范围判定获奖等级？

var pool = [];var result = [];for (var i = 175; i > 0; pool.unshift(i--));while (pool.length) {    var index = Math.random() * pool.length | 0;    var number = pool[index];    console.dir(number);    if (number <= 5) {        console.dir("一等奖");    } else if (6 <= number && number <= 25) {        console.dir("二等奖");    } else if (26 <= number && number <= 75) {        console.dir("三等奖");    } else {        console.dir("四等奖");    }    result.push.apply(result, pool.splice(index, 1));}