var tckn_ver = 8484786984;
function checkIdentityNumber(identityNumber)
{
    // For testing this check is disabled
    // return true;
    
    // for foreign students
	if(identityNumber.substring(0, 2) == "99")
		return true;
		
	// sebit test	
	if(identityNumber.substring(0, 5) == "sebit")
		return true;	
	
	var base = Math.floor(parseInt(identityNumber)/100);
	
	var digit1 = parseInt(identityNumber.substring(0, 1));
	var digit2 = parseInt(identityNumber.substring(1, 2));
	var digit3 = parseInt(identityNumber.substring(2, 3));
	var digit4 = parseInt(identityNumber.substring(3, 4));
	var digit5 = parseInt(identityNumber.substring(4, 5));
	var digit6 = parseInt(identityNumber.substring(5, 6));
	var digit7 = parseInt(identityNumber.substring(6, 7));
	var digit8 = parseInt(identityNumber.substring(7, 8));
	var digit9 = parseInt(identityNumber.substring(8, 9));
	
	var oddSum = digit9 + digit7 + digit5 + digit3 + digit1;
	var evenSum = digit8 + digit6 + digit4 + digit2;
	var total = oddSum*3 + evenSum;
	var check1 = (10-(total % 10)) % 10;
	
	oddSum = check1 + digit8 + digit6 + digit4 + digit2;
	evenSum  = digit9 + digit7 + digit5 + digit3 + digit1;
	total = oddSum*3 + evenSum;
	check2 = (10-(total % 10)) % 10;
	
	base = base*100 + check1*10 + check2;
   
	return (base == identityNumber);
}