js implements a rounding method that completely preserves two decimal places

In this paper, an example is given to describe the method of js to realize 4 rounding and 5 entering and completely retain two decimal places. Share it for your reference, as follows:

//4 Shed 5 Entry reservation 2 Decimal places (if the first 2 The decimal number of bits is 0 Is retained 1 Decimal bits) 
function keepTwoDecimal(num) {
  var result = parseFloat(num);
  if (isNaN(result)) {
    alert(' Error in passing parameters, please check! ');
    return false;
  }
  result = Math.round(num * 100) / 100;
  return result;
}
//4 Shed 5 Entry reservation 2 Decimal digits (if there are not enough digits, use 0 Substitutes) 
function keepTwoDecimalFull(num) {
  var result = parseFloat(num);
  if (isNaN(result)) {
    alert(' Error in passing parameters, please check! ');
    return false;
  }
  result = Math.round(num * 100) / 100;
  var s_x = result.toString();
  var pos_decimal = s_x.indexOf('.');
  if (pos_decimal < 0) {
    pos_decimal = s_x.length;
    s_x += '.';
  }
  while (s_x.length <= pos_decimal + 2) {
    s_x += '0';
  }
  return s_x;
}

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I hope this article is helpful to everyone's JavaScript programming.