/* *************************************************************
** FORMfields.JS - JS Form Validation Library
** =======================================
** This library contains code to validate HTML form-field data.

************************************************************* */

/* *************************************************************
** USAGE
** =====
** Functions to Validata Form-Element Data:
**   isEmpty(s) - true if string s is empty
**   isBlank(s) - true if string s is empty or blank (all whitespace chars)
**   isLetter(c) - true if char c is an English letter 
**   isDigit(c) - true if char c is a digit 
**   getCheckedSelectOptions(select) - gets index(es) of checked select options
**
** Functions to Reformat input:
**   stripBlanks(s) - removes all blank chars from s
**   stripLeadingBlanks(s) - removes leading blank chars from s
**   stripTrailingBlanks(s) - removes trailing blank chars from s
**   stripLeadingTrailingBlanks(s) - removes lead+trail blank chars from s
**   reformatString(targetStr, str1, int1 [, str2, int2 [, ..., ...]]) - 
**     inserts formatting chars or delimiters in targetStr (see below)
************************************************************* */


/* ********************************************************** */
/* Global Variables and Constants *************************** */
/* ********************************************************** */

var digits = "0123456789";
var lowercaseLetters = "abcdefghijklmnopqrstuvwxyz"
var uppercaseLetters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
var blanks = " \t\n\r";  // aka whitespace chars


/* ********************************************************** */
/* Functions ************************************************ */
/* ********************************************************** */


// Returns true if string s is empty

function isEmpty(s)
  {
  return ((s == null) || (s.length == 0));
  }


// Returns true if string s is empty or all blank chars

function isBlank(s)
  {
  var i;

  // Is s empty?
  if (isEmpty(s))
    return 1;
  else
	 return 0;

  // Search through string's chars one by one until we find first
  // non-blank char, then return false; if we don't, return true
  for (i=0; i<s.length; i++)
    {   
    // Check that current character isn't blank
    var c = s.charAt(i);
    if (blanks.indexOf(c) == -1) 
      return 0;
    }
  // All characters are blank
  return 1;

  }



// Removes all blank chars (as defined by blanks) from s

function stripBlanks(s)
  {
  return stripCharsInBag(s, blanks)
  }


// Removes leading blank chars (as defined by blanks) from s

function stripLeadingBlanks(s)
  { 
  var i = 0;
  while ((i < s.length) && (blanks.indexOf(s.charAt(i)) != -1))
     i++;
  return s.substring(i, s.length);
  }

// Removes trailing blank chars (as defined by blanks) from s


function stripTrailingBlanks(s)
  { 
  var i = s.length - 1;
  while ((i >= 0) && (blanks.indexOf(s.charAt(i)) != -1))
     i--;
  return s.substring(0, i+1);
  }


// Removes leading+trailing blank chars (as defined by blanks) from s

function stripLeadingTrailingBlanks(s)
  { 
  s = stripLeadingBlanks(s);
  s = stripTrailingBlanks(s);
  return s;
  }


// Returns true if character c is an English letter (A .. Z, a..z)

function isLetter(c)
  {
  return (((c >= "a") && (c <= "z")) || ((c >= "A") && (c <= "Z")));
  }


// Returns true if character c is a digit (0 .. 9)

function isDigit(s)
  {
	  for (i = 0; i < s.length; i++)
	  {   
		  // Check that current character is letter
		  var c = s.charAt(i);
	
		  if (!((c >= "0") && (c <= "9")))
		    return 0;
	  }
	
	  return 1;
  }


// Returns true if string s is English letters (A .. Z, a..z) only

function isAlphabetic(s)
  {
  var i;

  if (isBlank(s)) 
     return false;

  // Search through string's chars one by one until we find a 
  // non-alphabetic char, then return false; if we don't, return true

  for (i = 0; i < s.length; i++)
  {   
  // Check that current character is letter
  var c = s.charAt(i);

  if (!isLetter(c))
    return false;
  }

  // All characters are letters
  return true;
  }


// Returns true if string s is English letters (A .. Z, a..z) and numbers only

function isAlphanumeric(s)
  {
  var i;

  if (isBlank(s)) 
     return false;

  // Search through string's chars one by one until we find a 
  // non-alphanumeric char, then return false; if we don't, return true

  for (i = 0; i < s.length; i++)
    {   
    // Check that current character is number or letter
    var c = s.charAt(i);

    if (! (isLetter(c) || isDigit(c) ) )
    return false;
    }

  // All characters are numbers or letters
  return true;
  }



// Returns array containing index(es) of checked option(s) 
// in select box, or -1 if no options are selected

function getCheckedSelectOptions(select)
  {
  var arr = new Array();
  for (var i=0,j=0; i<select.length; i++)
    if (select.options[i].selected)
      arr[j++] = i;
  if (arr.length > 0)
    return arr;
  else
    return -1;
  }