function IsNumeric(sText) { if (sText == null) return false; var ValidChars = "0123456789"; var IsNumber = true; var Char; for (i = 0; i < sText.length && IsNumber == true; i++) { Char = sText.charAt(i); if (ValidChars.indexOf(Char) == -1) { IsNumber = false; } } return IsNumber; }