JavaScript: Check a credit card number format

JavaScript validation with regular expression: Exercise-2 with Solution

Validate Credit Card

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:

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"));

Output:

true
false

Flowchart:

Live Demo:

For more Practice: Solve these Related Problems:

• Write a JavaScript function that implements the Luhn algorithm to validate a credit card number.
• Write a JavaScript function that strips non-digit characters from a credit card input and then validates its length and checksum.
• Write a JavaScript function that checks if a given credit card number starts with valid issuer digits (e.g., 4 for Visa) and passes the Luhn test.
• Write a JavaScript function that accepts a credit card number as a string, removes spaces/hyphens, and returns whether it is valid based on standard rules.

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