CODEWITHSUNDEEP
javascriptjqueryasp.net-mvc-3
rohit
rohit

Reputation: 67

Credit card numbers starts with 1 & 15 digits long

i have written following jquery/javascript function for validating a credit card which is 15 digit long & must start with digit1. so, how would i validate that the number will start with digit 1.

if ($("#ddlCreditCardType" + i).val() == 'TP') {
                if (!($("#txtCreditCardNo" + i).val().length == 15)) {
                    $("#err" + i).html('Credit Card Number should be 15 digit');
                    status = 0;
                }
                else {
                    $("#err" + i).html('');
                    status = 1;
                }

Upvotes: 0

Views: 209

Answers (5)

Karim Harazin
Karim Harazin

Reputation: 1473

It is recommended to user regular expression to validate the credit card. Check this expression:

^1[0-9]{14}$

The description:

Options: case insensitive; ^ and $ match at line breaks

Assert position at the beginning of a line (at beginning of the string or after a line break character) «^»
Match the character “1” literally «1»
Match a single character in the range between “0” and “9” «[0-9]{14}»
   Exactly 14 times «{14}»
Assert position at the end of a line (at the end of the string or before a line break character) «$»

Example usage:

var credit = "123456789123456"; // lingth 15
alert(credit.match(/^1[0-9]{14}$/)); // will success

credit = "1234567891234567"; // lingth 16
alert(credit.match(/^1[0-9]{14}$/)); // will fail

credit = "5234567891234567"; // lingth 15, start with 5
alert(credit.match(/^1[0-9]{14}$/)); // will fail

Upvotes: 0

Saran
Saran

Reputation: 179

You can use regex also.

var c1='123456789012345';
var c2='234567890123456';
var regex=/^1\d{14}/; //regular expressions starting with '1' and the 14 digits at the end 
regex.exec(c1); //returns the c1
regex.exec(c2); //returns null

Upvotes: 0

frosty
frosty

Reputation: 21762

If you have to only support the most modern of browsers, you can do the following

var ccNum = $("#txtCreditCardNo" + i).val();
if(ccNum.startsWith('1')){
    //Do something cause it starts with 1
}

If you have to support older browsers, you could do the following, which works in newer and older browsers:

var ccNum = $("#txtCreditCardNo" + i).val();
if(ccNum.split('')[0] == '1'){
    //Do something cause it starts with 1
}

There are other options, but either of these would work.

Upvotes: 0

Yatendrasinh Joddha
Yatendrasinh Joddha

Reputation: 222

Use charAt function of JavaScript which allows you to read first character.

So in your code you can write:

if ($("#txtCreditCardNo" + i).val().charAt(0) == '1'){
// your code after validation
}

Upvotes: 0

Darin Dimitrov
Darin Dimitrov

Reputation: 1038850

You could take the first letter of the value and compare it with 1:

if ($("#ddlCreditCardType" + i).val() == 'TP') {
    var value = $("#txtCreditCardNo" + i).val();
    if (value.length !== 15 || value[0] !== '1') {
        $("#err" + i).html('Credit Card Number should be 15 digit and start with 1');
        status = 0;
    }
}

Upvotes: 2

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