JavaScript: Check a credit card number format

Last update on May 30 2022 10:00:50 (UTC/GMT +8 hours)

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>
<head>
  <meta charset="utf-8">
  <title>JavaScript function to check whether a given value is a valid credit card or not</title>
</head>
<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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JavaScript: Tips of the Day

How to insert an item into an array at a specific index (JavaScript)?

What you want is the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert). In this example we will create an array and add an element to it into index 2:

var arr = []; arr[0] = "Jani"; arr[1] = "Hege"; arr[2] = "Stale"; arr[3] = "Kai Jim"; arr[4] = "Borge"; console.log(arr.join()); arr.splice(2, 0, "Lene"); console.log(arr.join());

Ref: https://bit.ly/2BXbp04