# JavaScript: Check a credit card number format

## JavaScript validation with regular expression: Exercise-2 with Solution

Write a JavaScript program to check a credit card number.

Here are some format of some well-known credit cards.

• American Express :- Starting with 34 or 37, length 15 digits.
• Visa :- Starting with 4, length 13 or 16 digits.
• MasterCard :- Starting with 51 through 55, length 16 digits.
• Discover :- Starting with 6011, length 16 digits or starting with 5, length 15 digits.
• Diners Club :- Starting with 300 through 305, 36, or 38, length 14 digits.
• JCB :- Starting with 2131 or 1800, length 15 digits or starting with 35, length 16 digits.

Sample Solution:-

HTML Code:

``````<!DOCTYPE html>
<html>
<meta charset="utf-8">
<title>JavaScript function to check whether a given value is a valid credit card or not</title>
<body>

</body>
</html>
```
```

JavaScript Code:

``````function is_creditCard(str)
{
regexp = /^(?:(4[0-9]{12}(?:[0-9]{3})?)|(5[1-5][0-9]{14})|(6(?:011|5[0-9]{2})[0-9]{12})|(3[47][0-9]{13})|(3(?:0[0-5]|[68][0-9])[0-9]{11})|((?:2131|1800|35[0-9]{3})[0-9]{11}))\$/;

if (regexp.test(str))
{
return true;
}
else
{
return false;
}
}

console.log(is_creditCard("378282246310006"));

console.log(is_creditCard("37828224630006"));
```
```

Sample Output:

```true
false
```

Flowchart:

Live Demo:

See the Pen javascript-regexp-exercise-2 by w3resource (@w3resource) on CodePen.

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