javascript 从一组数组中随机取出一项

设计随机数

function selectNum( smallNum, BigNum) { 
    var youAll = BigNum - smallNum + 1; 
    return Math. floor( Math. random() * youAll + smallNum); 
}
var fruits = ["apple", "lemon", "banana", "pear", "watermelon", "honeydew", "pen"];
var fruit = fruits[ selectNum( 0, fruits. length- 1)];
console.log( fruit);

• 可以方便的从数组中取出随机的一项