function tidnes()

{

var i, s, t,  OutString;

	InString = '{jc/tfofdtAutf;pumjbn';

	OutString=new String();

	for(i=InString.length-1; i>= 0; i--)

	{

		t = InString.charCodeAt(i);

		s= String.fromCharCode(t-1);

		OutString += s;

	}



	return OutString;

}





// Mod 10 credit card number validator 

// Created by mattf (mattf@mail.com) 2002-09-13 

// This Software is Free with no implied warrantees or guarantees 

// You can use or modify this software any way you may like 

// Bodged into this form by J McAfee March 2003 

function Mod10(ccno) {

	vlengthgood=0;

	ccsum=0;

	badcard=false;

    ino=document.forms[0].issueno.value;

    card=document.forms[0].cardtype.value;

	s=card.search(/solo/i);

	t=card.search(/switch/i);

	if ((s!=t)&&(ino==""))

	{

		alert(card+"Requires an Issue Number");

		return false;

	}

	cclen=ccno.length;

	if (cclen<13)

	{

		badcard=true;

	}

	else

	{

		for (i=1; i<cclen; i++)

		{

			ccdig=parseInt(ccno.charAt(cclen-(i+1)));

			if (i%2==1)

			{

				ccdig*=2;

				if (ccdig.toString().length==2)

				{

					ccdig=(parseInt(ccdig.toString().charAt(0))+parseInt(ccdig.toString().charAt(1)));

				} 

			}

			ccsum+=ccdig;

		}

		ccsum+=parseInt(ccno.charAt(cclen-1));

		if (ccsum%10==0)

// Indicate the cards you don't accept by inserting a '*' at the start of the card name 

// Do NOT remove any of the card types or rearrange the processing order!!! 

// J McAfee 2003 

		{

				cc_type_id = '*NOT VALID TYPE';

			if (ccno.match(/^4/) )

				{cc_type_id = 'VISA';   if (cclen==13 || cclen==16) {vlengthgood=1;}   else {vlengthgood=0;} }

			if (ccno.match(/^50|^56|^57|^58|^6/) )

				{cc_type_id = 'MAESTRO';   vlengthgood=1;}

			if (ccno.match(/^51|^52|^53|^54|^55/) )

				{cc_type_id = 'MASTERCARD';   if (cclen==16) {vlengthgood=1;}   else {vlengthgood=0;} }

			if (ccno.match(/^413733|^413734|^413735|^413736|^413737|^4462|^453978|^453979|^454313|^454313|^454432|^454433|^454434|^454435|^454742|^456725|^456726|^456727|^456728|^456729|^45673|^456740|^456741|^456742|^456743|^456744|^456745|^46583|^46584|^46585|^46586|^46587|^484409|^484410|^49096|^49097|^492181|^492182|^498824/) )

				{cc_type_id = 'DELTA';   if (cclen==16) {vlengthgood=1;}   else {vlengthgood=0;} }

			if (ccno.match(/^450875|^484406|^484407|^484408|^484411|^484412|^484413|^484414|^484415|^484416|^484417|^484418|^484419|^48442|^48443|^48444|^484450|^484451|^484452|^484453|^484454|^484455|^49173|^49174|^49175|^491880/) )

				{cc_type_id = 'ELECTRON';   if (cclen==16) {vlengthgood=1;}   else {vlengthgood=0;} }

			if (ccno.match(/^405501|^405502|^405503|^405504|^405550|^405551|^405552|^405553|^405554|^415928|^424604|^424604|^427533|^4288|^443085|^4484|^4485|^4486|^4715|^4716|^4804/) )

				{cc_type_id = '*VISA PURCHASING';   if (cclen==16) {vlengthgood=1;}   else {vlengthgood=0;} }

			if (ccno.match(/^490300|^490301|^49031|^49032|^490330|^490331|^490332|^490333|^490334|^49034|^49035|^49036|^49037|^49038|^49039|^49040|^490419|^490451|^490459|^490467|^490475|^490476|^490477|^490478|^4905|^491103|^491104|^491105|^491106|^491107|^491108|^491109|^49111|^49112|^49113|^49114|^49115|^49116|^491170|^491171|^491172|^491173|^491183|^491184|^491185|^491186|^491187|^491188|^491189|^49119|^4928|^4987/) )

				{cc_type_id = '*VISA_ATM';   if (cclen==16) {vlengthgood=1;}   else {vlengthgood=0;} }

			if (ccno.match(/^60/) )

				{cc_type_id = '*DISCOVER';   if (cclen==16) {vlengthgood=1;}   else {vlengthgood=0;} }

			if (ccno.match(/^63345|^63346|^63347|^63348|^63349|^6767/) )

				{cc_type_id = 'SOLO';   if (cclen==16 || cclen==18 || cclen==19) {vlengthgood=1;}   else {vlengthgood=0;} }

			if (ccno.match(/^490302|^490303|^490304|^490305|^490306|^490307|^490308|^490309|^490335|^490336|^490337|^490338|^490339|^491101|^491102|^491174|^491175|^491176|^491177|^491178|^491179|^491180|^491181|^491182|^4936|^564182|^63330|^63331|^63332|^63333|^63334|^6759/) )

				{cc_type_id = 'SWITCH';   if (cclen==16 || cclen==18 || cclen==19) {vlengthgood=1;}   else {vlengthgood=0;} }

			if (ccno.match(/^34|^37/) )

				{cc_type_id = '*AMEX';   if (cclen==13 || cclen==15) {vlengthgood=1;}   else {vlengthgood=0;} }

			if (ccno.match(/^3528|^3529|^353|^354|^355|^356|^357|^358|^2131|^1800/) )

				{cc_type_id = 'JCB';   if (cclen==15 || cclen==16) {vlengthgood=1;}   else {vlengthgood=0;} }

			if (ccno.match(/^300|^301|^302|^303|^304|^305|^36|^380|^381|^382|^383|^384|^385|^386|^387|^388/) )

				{cc_type_id = '*DINERS CLUB';   if (cclen==14) {vlengthgood=1;}   else {vlengthgood=0;} }

			if (ccno.match(/^389/) )

				{cc_type_id = '*CARTE BLANCHE';   if (cclen==14) {vlengthgood=1;}   else {vlengthgood=0;} }

			if (ccno.match(/^2014|^2149/) )

				{cc_type_id = '*ENROUTE';   if (cclen==15) {vlengthgood=1;}   else {vlengthgood=0;} }



			if (cc_type_id.charAt(0)=="*") badcard=true;

			if (vlengthgood==0) badcard=true;

		} 

		else

		{

			badcard=true;

		}

	}

	if (badcard) 

	{

	 	alert("There appears to be an error in the credit card number");

		return false;

	}

	else

	{

		return true;

	}

}