10.千分位.html

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script>
        // 千分位
        const formatNum = (num, n = 1) => {
            var f = parseFloat(num);
            if (isNaN(f)) {
                return false;
            }
            f = Math.round(num * Math.pow(10, n)) / Math.pow(10, n); // n 幂
            var s = f.toString();
            var rs = s.indexOf('.');
            //判定如果是整数，增加小数点再补0
            if (rs < 0) {
                rs = s.length;
                s += '.';
            }
            while (s.length <= rs + n) {
                s += '0';
            }
            const regex = new RegExp(`(?!^)(?=(\\d{3})+${s.includes('.') ? '\\.' : '$'})`, 'g')
            return s.replace(regex, ',')
        }
        console.log(formatNum(1314520.678));


        // 创建临时id
        const randomString = () => Math.random().toString(36).slice(2);

        console.log(randomString());
    </script>
</head>

<body>

</body>

</html>