// checks if the input is numeric
function IsNumeric(sText)
{
   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;
		 break;
      }
   }
   return IsNumber;
}

// checks whether the input is numeric and within the specified range
function isValidNumber(input, min, max){
	var isValid = true;
	if (IsNumeric(input)){
		if (input < min || input > max){
			isValid = false;
		}
	} else {
		isValid = false;
	}
	return isValid;
}