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.Firstname.value == "") { 
   alert('Your firstname must be entered!'); 
   document.F.Firstname.focus(); 
   return false;
}
if (document.F.Surname.value == "") { 
    alert('Your surname must be entered!'); 
	document.F.Surname.focus();
	return false;
}
if (emailCheck(document.F.Email.value) == false) { 
	alert('You must enter a valid email address!'); 
	document.F.Email.focus();
	return false; 
}
if (document.F.Address1.value == "") { 
    alert('Your Address must be entered!'); 
	document.F.Address1.focus(); 
	return false;
}
if (document.F.TownCity.value == "") { 
    alert('Your Town/City must be entered!'); 
	document.F.TownCity.focus(); 
	return false;
}
if (document.F.Postcode.value == "") { 
    alert('Your Postcode must be entered!'); 
	document.F.Postcode.focus(); 
	return false;
}
if ((document.F.donation[document.F.donation.selectedIndex].value == "") && (document.F.textdonation.value == "")){
	alert('You must specify an amount to donate before proceeding to payment!');
	return false;
}

if ((document.F.donation[document.F.donation.selectedIndex].value != "") && (document.F.textdonation.value != "")){
	alert('You must choose a donation from the dropdown box OR specify an amount!');
	return false;
}
return true;
}

function checkIfNum(evt)
{
evt = (evt) ? evt :window.event
var charCode = (evt.which) ? evt.which : evt.keyCode
if (charCode <48 || charCode >57)
	{
	status = "This field accepts numbers only."
	return false
	}
	status = ""
	return true
}