可以使用以下PHP函数 验证一个卡号是否是信用卡
function
validateCard
(
$cardnumber
)
{
$cardnumber
=
preg_replace
(
"
/\D|\s/
"
,
""
,
$cardnumber
)
;
# strip any non-digits
$cardlength
=
strlen
(
$cardnumber
)
;
if
(
$cardlength
!=
0
)
{
$parity
=
$cardlength
%
2
;
$sum
=
0
;
for
(
$i
=
0
;
$i
<
$cardlength
;
$i
++
)
{
$digit
=
$cardnumber
[
$i
]
;
if
(
$i
%
2
==
$parity
)
$digit
=
$digit
*
2
;
if
(
$digit
>
9
)
$digit
=
$digit
-
9
;
$sum
=
$sum
+
$digit
;
}