function validate_personaldetails(form_name)
{

	if (form_name.username.value == "")
	{
		alert("Please choose a NickName for use on the site.");
		form_name.FirstName.focus();
		return false;
	}

	if (form_name.username.value != "")
	{
		var string2check = form_name.username.value
		if (!AlphaNum(string2check))
		{
			alert("Sorry, Your NickName must only contain alphanumeric characters (abc.. 123..).\nUse a dash or an underscore instead of a space");
			form_name.username.focus();
			return false;
		}
	}	

	if (form_name.UsrNameInuse.value == "1")
	{
		alert("The nickname "+ form_name.username.value +" is already in use!");
		form_name.FirstName.focus();
		return false;
	}


	if (form_name.FirstName.value == "")
	{
		alert("What's your first name?\nYour name will never be displayed on the site!");
		form_name.FirstName.focus();
		return false;
	}

	if (form_name.LastName.value == "")
	{
		alert("What's your last name?\nYour name will never be displayed on the site!");
		form_name.LastName.focus();
		return false;
	}

	if (form_name.GSM.value != "")
	{
		//remove spaces from the telephone number to help validation
		var mob = removeSpaces(form_name.GSM.value);
		// Remove hyphens from the telephone number to help validation
		while (mob.indexOf("-")!= -1)  
		{
		mob = mob.slice (0,mob.indexOf("-")) + mob.slice (mob.indexOf("-")+1)
		}  

		//update form field
		form_name.GSM.value = mob;
		//get the value with no spaces
		var mob = form_name.GSM.value;

		if (isNaN(mob))
		{
			alert("Please enter a valid Mobile Number");
			form_name.GSM.select();
			form_name.GSM.focus();
			return false;
		}

		//deal with UK mobile
		if (mob.indexOf("07")== 0)
		{
			mob = "00447" + mob.substring(2,mob.length)
			//alert(mob)
		}
		//deal with IRISH mobile
		if (mob.indexOf("08")== 0)
		{
			mob = "003538" + mob.substring(2,mob.length)
			//alert(mob)
		}

		//return the result
		form_name.GSM.value = mob;

		if (mob.length< 7)
		{
			alert("Please enter a valid Mobile Number: the one you've entered is too short.");
			form_name.GSM.select();
			form_name.GSM.focus();
			return false;
		}

		if (mob.length > 15)
		{
			alert("Please enter a valid Mobile Number: the one you've entered is too long.");
			form_name.GSM.select();
			form_name.GSM.focus();
			return false;
		}


	}


	if (!CheckGender(form_name))
 	{
 		alert("Are you a male or a female?");
		form_name.gender.focus();
		return false;
	}


	if (form_name.password.value == "")
	{
		alert("Please choose a password!");
		form_name.password.select();
		return false;
	}

	if (!AlphaNum(form_name.password.value))
	{
		alert("Sorry, you can only use alphanumeric in your password");
		form_name.password.focus();
		return false;
	}

	if (form_name.password.value != "")
	{
		var password = form_name.password.value
		var common = "password"

		if (password == common)
		{
		//alert (password + " " + common)

		alert("For security reason, your password can't be <<password>>!");
		form_name.password.select();
		return false;
		}

		var common2 = "password"
		if (password == common2)
		{
		//alert (password + " " + common2)

		alert("For security reason, your password can't be <<password>>!");
		form_name.password.select();
		return false;
		}
	}

	if (form_name.username.value == form_name.password.value)
	{
		alert("For security reason, your password can't be the same as your nickname \nsorry!");
		form_name.password.select();
		return false;
	}


	if (form_name.password.value.length < 4)
	{
		alert("Your password must be more than 4 characters in length!");
		form_name.password.select();
		return false;
	}

	if (form_name.password.value.length > 20)
	{
		alert("Your password must be less than 20 characters in length!");
		form_name.password.select();
		return false;
	}

	if (form_name.email.value == "")
	{
		alert("what's your email address?\nYour email will never be displayed on the site!");
		form_name.email.select();
		return false;
	}

	if (form_name.email.value != "")
	{
		
		var emailStr=form_name.email.value;
		var emailPat=/^(.+)@(.+)$/
		var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]"
		var validChars="\[^\\s" + specialChars + "\]"
		var quotedUser="(\"[^\"]*\")"
		var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/
		var atom=validChars + '+'
		var word="(" + atom + "|" + quotedUser + ")"
		var word2 = "(" + validChars + "*|" + quotedUser + ")";
		var userPat=new RegExp("^" + word + "(\\." + word2 + ")*$")

		//var userPat=new RegExp("^" + word + "(\\." + word + ")*$")
		var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$")
		var matchArray=emailStr.match(emailPat)
		if (matchArray==null) {
			alert("Invalid email address! (error1)")
			form_name.email.select();
			return false;
		}
		var user=matchArray[1]
		var domain=matchArray[2]
		if (user.match(userPat)==null) {
			alert("Invalid email address! (error2)")
			form_name.email.select();
			return false;
		}
		var IPArray=domain.match(ipDomainPat)
		if (IPArray!=null) {
			  for (var i=1;i<=4;i++) {
				if (IPArray[i]>255) {
					alert("Invalid email address! (error3)")
				form_name.email.select();
				return false;
				}
			}
			//return true;
		}
		var domainArray=domain.match(domainPat)
		if (domainArray==null) {
			alert("Invalid email address! (error4)")
			form_name.email.select();
			return false;
		}
		var atomPat=new RegExp(atom,"g")
		var domArr=domain.match(atomPat)
		var len=domArr.length
		if (domArr[domArr.length-1].length<2 ||
			domArr[domArr.length-1].length>3) {
		   alert("Invalid email address! (error5)")
		   form_name.email.select();
		   return false;
		}
		if (len<2) {
		   alert("Invalid email address! Address Too Short!")
		   form_name.email.select();
		   return false;
		}
	}

	// T & C
	if (form_name.TC.checked==false)
	{
		alert("You must agree to the terms and conditions of the site to continue!");
		return false;
	}

	var dobd = document.join.dobday.options[document.join.dobday.selectedIndex].value;
	var dobm = document.join.dobmonth.options[document.join.dobmonth.selectedIndex].value;
	var doby = document.join.dobyear.options[document.join.dobyear.selectedIndex].value;
	var dob = dobd + ' ' + dobm + ' ' + doby;

	if (IsDate(dob)==false)
	{
		alert("What's your Date of Birth?");
		return false;
	}

	
	if ( CalcDiffYears(dob, new Date())<18)
	{
		alert("Sorry, you must be 18 to regsiter!");
		return false;
	}

return true;
}


function CheckGender(form_name)
{
	var myOption = 0;
	myOption = document.join.gender.selectedIndex;
	if (myOption == 0) 
	{
		return false;
	}
	else
	{
		return true;
	}
}

function AlphaNum(string2check)
{
	// allow ONLY alphanumeric keys, no symbols or punctuation
	// this can be altered for any "checkOK" string you desire
	var checkOK = "_-ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
	var checkStr = string2check;
	var allValid = true;
	for (i = 0;  i < checkStr.length;  i++)
	{
		ch = checkStr.charAt(i);
		for (j = 0;  j < checkOK.length;  j++)
		if (ch == checkOK.charAt(j))
		break;
		if (j == checkOK.length)
		{
			allValid = false;
			break;
		}
	}
	if (!allValid)
	{
		return (false);
	}
	else
	{
		return (true);
	}

}


function removeSpaces(string) 
{
	return string.split(' ').join('');
}