50分求救：用JAVASCRIPT写MOD/10验证卡号的例子，在线等待中。。。

[老李]

谢谢了！

[qiushuiwuhen]

http://developer.netscape.com/docs/examples/javascript/formval/overview.html

[qiushuiwuhen]

view-source:http://developer.netscape.com/docs/examples/javascript/formval/FormChek.js

代码
function isCreditCard(st) {
// Encoding only works on cards with less than 19 digits
if (st.length > 19)
return (false);

sum = 0; mul = 1; l = st.length;
for (i = 0; i < l; i++) {
digit = st.substring(l-i-1,l-i);
tproduct = parseInt(digit ,10)*mul;
if (tproduct >= 10)
sum += (tproduct % 10) + 1;
else
sum += tproduct;
if (mul == 1)
mul++;
else
mul--;
}
// Uncomment the following line to help create credit card numbers
// 1. Create a dummy number with a 0 as the last digit
// 2. Examine the sum written out
// 3. Replace the last digit with the difference between the sum and
// the next multiple of 10.

// document.writeln("<BR>Sum = ",sum,"<BR>");
// alert("Sum = " + sum);

if ((sum % 10) == 0)
return (true);
else
return (false);

} // END FUNCTION isCreditCard()

[老李]

老是出错，秋水你调试过吗？

[qiushuiwuhen]

<form>
<input id=tt value=3141592653587><input type=button value=check onclick=check(tt.value)>
</form>
<script>
function check(str){
if(!isCreditCard(str))alert("未通过")
alert("通过第一层验证："+str)
}
function isCreditCard(st) {
// Encoding only works on cards with less than 19 digits
if (st.length > 19)
return (false);

sum = 0; mul = 1; l = st.length;
for (i = 0; i < l; i++) {
digit = st.substring(l-i-1,l-i);
tproduct = parseInt(digit ,10)*mul;
if (tproduct >= 10)
sum += (tproduct % 10) + 1;
else
sum += tproduct;
if (mul == 1)
mul++;
else
mul--;
}
// Uncomment the following line to help create credit card numbers
// 1. Create a dummy number with a 0 as the last digit
// 2. Examine the sum written out
// 3. Replace the last digit with the difference between the sum and
// the next multiple of 10.

// document.writeln("<BR>Sum = ",sum,"<BR>");
// alert("Sum = " + sum);

if ((sum % 10) == 0)
return (true);
else
return (false);

} // END FUNCTION isCreditCard()
</script>

[孟子E章]

你的卡号什么特征？

[老李]

16位全数字的。