var msg = "";
function GetCheckDigit13(val)
{
	msg = "";
	if(checkval(val,12))
	{
		factor = 3;
	  	sum = 0;
		for (index = val.length; index > 0; --index)
		{
			sum = sum + val.substring (index-1, index) * factor;
			factor = 4 - factor;
	  	}
	  	return (1000 - sum) % 10;
	}
	else
	{
		return "";
	}
}
function GetCheckDigit8(val)
{
	msg = "";
	if(checkval(val,7))
	{
		factor = 3;
	  	sum = 0;
		for (index = val.length; index > 0; --index)
		{
			sum = sum + val.substring (index-1, index) * factor;
			factor = 4 - factor;
	  	}
	  	return (1000 - sum) % 10;
	}
	else
	{
		return "";
	}
}
function GetCheckDigit14(val)
{	
	msg = "";
	if(checkval(val,13))
	{
		factor = 3;
	  	sum = 0;
		for (index = val.length; index > 0; --index)
		{
			sum = sum + val.substring (index-1, index) * factor;
			factor = 4 - factor;
	  	}
	  	return (1000 - sum) % 10;
	}
	else
	{
		return "";
	}
}

function GetCheckDigit12(val)
{	
	msg = "";
	if(checkval(val,11))
	{
		factor = 3;
	  	sum = 0;
		for (index = val.length; index > 0; --index)
		{
			sum = sum + val.substring (index-1, index) * factor;
			factor = 4 - factor;
	  	}
	  	return (1000 - sum) % 10;
	}
	else
	{
		return "";
	}
}

function GetMessage()
{
	return msg;
}
function checkval(val,digit)
{
	if(val.length == "")
	{
		msg = "入力されていません。";
		return false;
	}
	if(isNaN(val))
	{
		msg = "数字以外の文字が検出されました。";
		return false;
	}
	if(val.length != digit)
	{
		msg = "桁数が足りません。\n" + digit + "桁の数字を入力してください。";
		return false;
	}
	return true;
}