function mod10( cardNumber ) { // LUHN Formula for validation of credit card numbers.
var ar = new Array( cardNumber.length );
var i = 0,sum = 0;


for( i = 0; i < cardNumber.length; ++i ) {
ar[i] = parseInt(cardNumber.charAt(i));
}
for( i = ar.length -2; i >= 0; i-=2 ) { // you have to start from the right, and work back.
ar[i] *= 2;							 // every second digit starting with the right most (check digit)
if( ar[i] > 9 ) ar[i]-=9;			 // will be doubled, and summed with the skipped digits.
}										 // if the double digit is > 9, ADD those individual digits together 


for( i = 0; i < ar.length; ++i ) {
sum += ar[i];						 // if the sum is divisible by 10 mod10 succeeds
}
return (((sum%10)==0)?true:false);	 	
}


function expired( month, year ) {
year = eval("20" + year);
var now = new Date();							// this function is designed to be Y2K compliant.
var expiresIn = new Date(year,month,0,0,0);
if( now.getTime() < expiresIn.getTime() ) return false;
return true;									// then we get the miliseconds, and do a long integer comparison
}





function chkalpha(str){
  var re =  /^[a-zA-Z]+$/;
	if (re.test(str))
	{
		return true;
	}
	else
	{
		return false;
	}
}