js实现的格式化数字和金额功能简单示例

function number_format(number, decimals, dec_point, thousands_sep) {
  /*
  * 参数说明：
  * number：要格式化的数字
  * decimals：保留几位小数
  * dec_point：小数点符号
  * thousands_sep：千分位符号
  * */
  number = (number + '').replace(/[^0-9+-Ee.]/g, '');
  var n = !isFinite(+number) ? 0 : +number,
    prec = !isFinite(+decimals) ? 0 : Math.abs(decimals),
    sep = (typeof thousands_sep === 'undefined') ? ',' : thousands_sep,
    dec = (typeof dec_point === 'undefined') ? '.' : dec_point,
    s = '',
    toFixedFix = function (n, prec) {
      var k = Math.pow(10, prec);
      return '' + Math.ceil(n * k) / k;
    };
  s = (prec ? toFixedFix(n, prec) : '' + Math.round(n)).split('.');
  var re = /(-?\d+)(\d{3})/;
  while (re.test(s[0])) {
    s[0] = s[0].replace(re, "$1" + sep + "$2");
  }
  if ((s[1] || '').length < prec) {
    s[1] = s[1] || '';
    s[1] += new Array(prec - s[1].length + 1).join('0');
  }
  return s.join(dec);
}

var num=number_format(1234567.089, 2, ".", ",");//1,234,567.09
console.log(num);

function number_format(number, decimals, dec_point, thousands_sep) {
    /*
    * 参数说明：
    * number：要格式化的数字
    * decimals：保留几位小数
    * dec_point：小数点符号
    * thousands_sep：千分位符号
    * */
    number = (number + '').replace(/[^0-9+-Ee.]/g, '');
    var n = !isFinite(+number) ? 0 : +number,
      prec = !isFinite(+decimals) ? 0 : Math.abs(decimals),
      sep = (typeof thousands_sep === 'undefined') ? ',' : thousands_sep,
      dec = (typeof dec_point === 'undefined') ? '.' : dec_point,
      s = '',
      toFixedFix = function (n, prec) {
        var k = Math.pow(10, prec);
        return '' + Math.floor(n * k) / k;
      };
    s = (prec ? toFixedFix(n, prec) : '' + Math.floor(n)).split('.');
    var re = /(-?\d+)(\d{3})/;
    console.log(s)
    while (re.test(s[0])) {
      s[0] = s[0].replace(re, "$1" + sep + "$2");
    }
    if ((s[1] || '').length < prec) {
      s[1] = s[1] || '';
      s[1] += new Array(prec - s[1].length + 1).join('0');
    }
    return s.join(dec);
}
var num=number_format(1234567.089, 2, ".", ",");//1,234,567.08
console.log(num)