4	5	6	3	9	6	0	1	2	2	0	0	1	9	9	9
x2	x1	x2	x1	x2	x1	x2	x1	x2	x1	x2	x1	x2	x1	x2	x1
4x2 = 8	5	6x2 = 12	3	9x2 = 18	6	0x2 = 0	1	2x2 = 4	2	0x2 = 0	0	1x2 = 2	9	9x2 = 18	9
8	5	(12) 1+2 = 3	3	(18) 1+8 = 9	6	0	1	4	2	0	0	2	9	(18) 1+8 = 9	9
8 +	5 +	3 +	3 +	9 +	6 +	0 +	1 +	4 +	2 +	0 +	0 +	2 +	9 +	9 +	9	= 70

Now we mod the sum by 10, if the remian is Zero the nuber is valid
OK : 70 Mod 10 = 0

JavaScript Luhn Credit Card number Validation

<script>
	var cardValid=function(cardNo){    
    var sum = 0, iNum;
    for( var i in cardNo+='' ){
		iNum = parseInt(cardNo[i]);
		sum += i%2?iNum:iNum>4?iNum*2%10+1:iNum*2;
    }
    return !(sum%10);
  };
</script>


Asp vb script IsraCard Credit Card number Validation (8 or 9 digits)

<%
Function IsraCardCheck(strNumber)
	comp1 = "987654321"
	comp2 = strNumber
	srez = 0
	if len(comp2) < 9 then comp2 = "0" & comp2
	for i = 1 to 9 
		a = mid(comp1, i, 1)
		b = mid(comp2, i, 1)
		c = a * b
		srez = srez + c
	next
	
	if srez mod 11 = 0 then
		IsraCheck = true
	else
		IsraCheck = false
	end if
End Function 
%>