/*==================================================================================================

Application:   Utility Function
Author:        John Gardner

Version:       V1.0
Date:          18th November 2003
Description:   Used to check the validity of a UK postcode

Version:       V2.0
Date:          8th March 2005
Description:   BFPO postcodes implemented.
               The rules concerning which alphabetic characters are allowed in which part of the
               postcode were more stringently implementd.

Version:       V3.0
Date:          8th August 2005
Description:   Support for Overseas Territories added

Version:       V3.1
Date:          23rd March 2008
Description:   Problem corrected whereby valid postcode not returned, and 'BD23 DX' was invalidly
               treated as 'BD2 3DX' (thanks Peter Graves)

Version:       V4.0
Date:          7th October 2009
Description:   Character 3 extended to allow 'pmnrvxy' (thanks to Jaco de Groot)

Version:       V4.1
               8th September 2011
               Support for Anguilla overseas territory added

Parameters:    toCheck - postcodeto be checked.

This function checks the value of the parameter for a valid postcode format. The space between the
inward part and the outward part is optional, although is inserted if not there as it is part of the
official postcode.

If the postcode is found to be in a valid format, the function returns the postcode properly
formatted (in capitals with the outward code and the inward code separated by a space. If the
postcode is deemed to be incorrect a value of false is returned.

Example call:

  if (checkPostCode (myPostCode)) {
    alert ("Postcode has a valid format")
  }
  else {alert ("Postcode has invalid format")};

--------------------------------------------------------------------------------------------------*/

function checkPostCode2 (toCheck) {

  // Permitted letters depend upon their position in the postcode.
  var alpha1 = "[abcdefghijklmnoprstuwyz]";                       // Character 1
  var alpha2 = "[abcdefghklmnopqrstuvwxy]";                       // Character 2
  var alpha3 = "[abcdefghjkpmnrstuvwxy]";                         // Character 3
  var alpha4 = "[abehmnprvwxy]";                                  // Character 4
  var alpha5 = "[abdefghjlnpqrstuwxyz]";                          // Character 5

  // Array holds the regular expressions for the valid postcodes
  var pcexp = new Array ();

  // Expression for postcodes: AN NAA, ANN NAA, AAN NAA, and AANN NAA
  pcexp.push (new RegExp ("^(" + alpha1 + "{1}" + alpha2 + "?[0-9]{1,2})(\\s*)([0-9]{1}" + alpha5 + "{2})$","i"));

  // Expression for postcodes: ANA NAA
  pcexp.push (new RegExp ("^(" + alpha1 + "{1}[0-9]{1}" + alpha3 + "{1})(\\s*)([0-9]{1}" + alpha5 + "{2})$","i"));

  // Expression for postcodes: AANA  NAA
  pcexp.push (new RegExp ("^(" + alpha1 + "{1}" + alpha2 + "{1}" + "?[0-9]{1}" + alpha4 +"{1})(\\s*)([0-9]{1}" + alpha5 + "{2})$","i"));

  // Exception for the special postcode GIR 0AA
  pcexp.push (/^(GIR)(\s*)(0AA)$/i);

  // Standard BFPO numbers
  pcexp.push (/^(bfpo)(\s*)([0-9]{1,4})$/i);

  // c/o BFPO numbers
  pcexp.push (/^(bfpo)(\s*)(c\/o\s*[0-9]{1,3})$/i);

  // Overseas Territories
  pcexp.push (/^([A-Z]{4})(\s*)(1ZZ)$/i);

  // Anguilla
  pcexp.push (/^(ai-2640)$/i);

  // Load up the string to check
  var postCode = toCheck;

  // Assume we're not going to find a valid postcode
  var valid = false;

  // Check the string against the types of post codes
  for ( var i=0; i<pcexp.length; i++) {
    if (pcexp[i].test(postCode)) {

      // The post code is valid - split the post code into component parts
      pcexp[i].exec(postCode);

      // Copy it back into the original string, converting it to uppercase and inserting a space
      // between the inward and outward codes
      postCode = RegExp.$1.toUpperCase() + " " + RegExp.$3.toUpperCase();

      // If it is a BFPO c/o type postcode, tidy up the "c/o" part
      postCode = postCode.replace (/C\/O\s*/,"c/o ");

      // If it is the Anguilla overseas territory postcode, we need to treat it specially
      if (toCheck.toUpperCase() == 'AI-2640') {postCode = 'AI-2640'};

      // Load new postcode back into the form element
      valid = true;

      // Remember that we have found that the code is valid and break from loop
      break;
    }
  }

  // Return with either the reformatted valid postcode or the original invalid postcode
  if (valid) {return postCode;} else return false;
}


function checkPostCode (toCheck) {
	var patt1=/^(GIR[ ]?0AA)$|^([A-PR-UWYZ][0-9][ ]?[0-9][ABD-HJLNPQ-UW-Z]{2})$|^([A-PR-UWYZ][0-9][0-9][ ]?[0-9][ABD-HJLNPQ-UW-Z]{2})$|^([A-PR-UWYZ][A-HK-Y0-9][0-9][ ]?[0-9][ABD-HJLNPQ-UW-Z]{2})$|^([A-PR-UWYZ][A-HK-Y0-9][0-9][0-9][ ]?[0-9][ABD-HJLNPQ-UW-Z]{2})$|^([A-PR-UWYZ][0-9][A-HJKS-UW0-9][ ]?[0-9][ABD-HJLNPQ-UW-Z]{2})$|^([A-PR-UWYZ][A-HK-Y0-9][0-9][ABEHMNPRVWXY0-9][ ]?[0-9][ABD-HJLNPQ-UW-Z]{2})$/;
	if(toCheck.match(patt1)) {
		return true;
	}
	return false;
}