JS如何输出数字（每三位加逗号）

function toThousands(num) {
    var result = '', counter = 0;
    num = (num || 0).toString();
    for (var i = num.length - 1; i >= 0; i--) {
        counter++;
        result = num.charAt(i) + result;
        console.log('charat res'+result);
        if (!(counter % 3) && i != 0) {
            result = ',' + result;
        }
    }
    return result;
}

转自：https://blog.csdn.net/qq_37958260/article/details/80406851