Decimal or numeric values in regular expression validation

Question

I am trying to use a regular expression validation to check for only decimal values or numeric values. But user enters numeric value, it don\'t be first digit \"0\"

Answer 1

I had the same problem, but I also wanted ".25" to be a valid decimal number. Here is my solution using JavaScript:

function isNumber(v) {
  // [0-9]* Zero or more digits between 0 and 9  (This allows .25 to be considered valid.)
  // ()? Matches 0 or 1 things in the parentheses.  (Allows for an optional decimal point)
  // Decimal point escaped with \.
  // If a decimal point does exist, it must be followed by 1 or more digits [0-9]
  // \d and [0-9] are equivalent 
  // ^ and $ anchor the endpoints so tthe whole string must match.
  return v.trim().length > 0 && v.trim().match(/^[0-9]*(\.[0-9]+)?$/);
}

Where my trim() method is

String.prototype.trim = function() {
  return this.replace(/(^\s*|\s*$)/g, "");
};

Matthew DesVoigne