javascript生成指定位数的随机数

1、定义用于生成随机数的种子

const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';

2、通过Math.random()生成随机数
3、示例代码

function generateCaptcha(length = 4) {
    const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
    let captcha = '';

    for (let i = 0; i < length; i++) {
        const randomIndex = Math.floor(Math.random() * characters.length);
        captcha += characters[randomIndex];
    }
    return captcha
}

4、调用

generateCaptcha(8) // UDC4I2ID