javascript实现的数字格式化代码下载

<script>
var format=function (number,form){
  var forms=form.split('.');
  var number=''+number;
  var numbers=number.split('.');
  var leftnumber=numbers[0].split('');
  var exec=function(lastMatch){
    if(lastMatch=='0'||lastMatch=='#') {
      if(leftnumber.length) {
        return leftnumber.pop();
      } else if(lastMatch=='0') {
        return lastMatch;
      } else {
        return '';
      }
    } else {
      return lastMatch;
    }
  }
  var string;
  string=forms[0].split('').reverse().join('').replace(/./g, exec).split('').reverse().join('');
  string=leftnumber.join('') + string;
  
  if(forms[1]&&forms[1].length){
    leftnumber = (numbers[1] && numbers[1].length) ? numbers[1].split('').reverse() : [];
    string += '.' + forms[1].replace(/./g, exec);
  }
  return string.replace(/\\.$/, '');
}
console.log(format(123,'#.00'))
console.log(format(123,'0.##'))                
console.log(format(123,'0000.00 '))
console.log(format(123456,'###,###.00'))
</script>