function checkPostCode (toCheck) {

  // Permitted letters depend upon their position in the postcode.
  var alpha1 = "[abcdefghijklmnoprstuwyz]";                       // Character 1
  var alpha2 = "[abcdefghklmnopqrstuvwxy]";                       // Character 2
  var alpha3 = "[abcdefghjkstuw]";                                // 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 + "?[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);

  // 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 ");
      
      // 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 emailCheck (emailStr) {
  emailStr = emailStr.toLowerCase();
  var checkTLD=1;
  var knownDomsPat=/^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/;
  var emailPat=/^(.+)@(.+)$/;
  var specialChars="\\(\\)><@,;:\\\\\\\"\\.\\[\\]";
  var validChars="\[^\\s" + specialChars + "\]";
  var quotedUser="(\"[^\"]*\")";
  var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/;
  var atom=validChars + '+';
  var word="(" + atom + "|" + quotedUser + ")";
  var userPat=new RegExp("^" + word + "(\\." + word + ")*$");
  var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$");
  var matchArray=emailStr.match(emailPat);

  if (matchArray==null) { return false; }
  var user=matchArray[1];
  var domain=matchArray[2];

  for (i=0; i<user.length; i++) {
    if (user.charCodeAt(i)>127) {
      return false;
    }
  }

  for (i=0; i<domain.length; i++) {
    if (domain.charCodeAt(i)>127) {
      return false;
    }
  }

  if (user.match(userPat)==null) {
    return false;
  }

  var IPArray=domain.match(ipDomainPat);
  if (IPArray!=null) {
    for (var i=1;i<=4;i++) {
      if (IPArray[i]>255) {
        return false;
      }
    }
    return true;
  }

  var atomPat=new RegExp("^" + atom + "$");
  var domArr=domain.split(".");
  var len=domArr.length;
  for (i=0;i<len;i++) {
    if (domArr[i].search(atomPat)==-1) {
      return false;
    }
  }

  if (checkTLD && domArr[domArr.length-1].length!=2 && domArr[domArr.length-1].search(knownDomsPat)==-1) { return false; }
  if (len<2) { return false; }
  // If we've gotten this far, everything's valid!
  return true;
}

// whitespace characters
var whitespace = " \t\n\r";

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

function isWhitespace (s) {
  var i;

  if (isEmpty(s)) return true;
  for (i = 0; i < s.length; i++) {   
    // Check that current character isn't whitespace.
    var c = s.charAt(i);
    if (whitespace.indexOf(c) == -1) return false;
  }
  // All characters are whitespace.
  return true;
}

function isValidFieldWithCharacters (s, minlength) {
  if (isWhitespace(s)) return false;
  if (stripWhitespace(s).length < minlength) return false;
  return true;
}

function stripWhitespace (s) {   
  return stripCharsInBag (s, whitespace)
}

function stripCharsInBag (s, bag) {
  var i;
  var returnString = "";

  for (i = 0; i < s.length; i++) {   
    // Check that current character isn't whitespace.
    var c = s.charAt(i);
    if (bag.indexOf(c) == -1) returnString += c;
  }
  return returnString;
}

function validateNumeric(ValueToCheck) {
	var valid = "0123456789"
	var ok = "yes";
	var temp;
	
	for (var i=0; i < ValueToCheck.length; i++) {
		temp = "" + ValueToCheck.substring(i, i+1);
		if (valid.indexOf(temp) == "-1") ok = "no";
	}

	if (ok == "no") {
		return false;
	} else {
		return true;
	}
}

function ValidateData() {


if (document.F.Contact0FirstName.value == "") { 
   alert('Your firstname must be entered!'); 
   document.F.Contact0FirstName.focus(); 
   return false;
}
if (document.F.Contact0LastName.value == "") { 
    alert('Your surname must be entered!'); 
	document.F.Contact0LastName.focus();
	return false;
}
if (emailCheck(document.F.Contact0Email.value) == false) { 
	alert('You must enter a valid email address!'); 
	document.F.Contact0Email.focus();
	return false; 
}

return true;
}