const toDecimal2 = (x) => {  var f = parseFloat(x);  if (isNaN(f)) {    return false;  }  var f = Math.round(x * 100) / 100;  var s = f.toString();  var rs = s.indexOf('.');  if (rs < 0) {    rs = s.length;    s += '.';  }  while (s.length <= rs + 2) {    s += '0';  }  return s;};const FenToYuan = (fen) => {  var num = fen;  num = fen * 0.01;  num += '';  var reg =    num.indexOf('.') > -1      ? /(\d{1,3})(?=(?:\d{3})+\.)/g      : /(\d{1,3})(?=(?:\d{3})+$)/g;  num = num.replace(reg, '$1');  num = toDecimal2(num);  return num;};for (let i = 10000; i < 100000; i++) {  const n = FenToYuan(i);  console.log(n);  if (n.length > 9) {    console.log(n.length);  }}原文:https://juejin.cn/post/7099650508591202341