function checkPostCode (toCheck) 
{
  // This 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 (/^([a-z]{1,2}[0-9]{1,2})(\s*)([0-9]{1}[abdefghijlnpqrstuwxyx][a-z])$/i);

  // Expression for postcodes: ANA NAA, and AANA  NAA
  pcexp.push (/^([a-z]{1,2}[0-9]{1}[a-z]{1})(\s*)([0-9]{1}[abdefghijlnpqrstuwxyx][a-z])$/i);

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

      // 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 test_code() 
{
	var frm = document.frm_pcsearch;

	if (checkPostCode (frm.pc.value)) 
	{
		frm.pc.value=checkPostCode (frm.pc.value);
		frm.action = 'searchresults.php?action=search';
		frm.submit();
	} 
	else 
	{
		alert('Please enter a valid postcode');
	}
}