每3位加逗号
var num = prompt('输入大数字', '25000000')
// 我写的
function douhao(num) {
num = Array.from(num.toString())
for (var i = num.length - 3; i > 0; i -= 3) {
num.splice(i, 0, ',')
}
console.log(num.join(''));
}
// douhao(num)
// 参考答案
function toThousands(num) {
var num = num.toString(),
result = ''
while (num.length > 3) {
result = ',' + num.slice(-3) + result;
num = num.slice(0, num.length - 3);
}
if (num) { result = num + result; }
console.log(result);
}
// toThousands(num)