One-time Passwords (OTP) is a password that is valid for only one login session or transaction on a computer or a digital device. Nowadays OTP’s are used in almost every service like Internet Banking, online transactions, etc. They are generally a combination of 4 or 6 numeric digits or a 6-digit alphanumeric. The random function is used to generate random OTP which is predefined in the Math library. This article describes how to generate OTP using JavaScript.
Used Function:
- Math.random(): This function returns any random number between 0 to 1.
- Math.floor(): It returns floor of any floating number to a integer value.
Using the above function pick a random index of string array which contains all the possible candidates of a particular digit of the OTP.
Example 1: This example generates 4 digit Numeric OTP:
<script> // Function to generate OTP function generateOTP() { // Declare a digits variable // which stores all digits var digits = '0123456789'; let OTP = ''; for (let i = 0; i < 4; i++ ) { OTP += digits[Math.floor(Math.random() * 10)]; } return OTP; } document.write("OTP of 4 digits: ") document.write( generateOTP() ); </script> |
Output:
OTP of 4 digits: 2229
Example 2: This example generates 6 digit Numeric OTP:
<script> // Function to generate OTP function generateOTP() { // Declare a digits variable // which stores all digits var digits = '0123456789'; let OTP = ''; for (let i = 0; i < 6; i++ ) { OTP += digits[Math.floor(Math.random() * 10)]; } return OTP; } document.write("OTP of 6 digits: ") document.write( generateOTP() ); </script> |
Output:
OTP of 6 digits: 216664
Example 3: This example generates alphanumeric OTP of length 6:
<script> // Function to generate OTP function generateOTP() { // Declare a string variable // which stores all string var string = '0123456789abcdefghijklmnopqrs tuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'; let OTP = ''; // Find the length of string var len = string.length; for (let i = 0; i < 6; i++ ) { OTP += string[Math.floor(Math.random() * len)]; } return OTP; } document.write("OTP of 6 length: ") document.write( generateOTP() ); </script> |
Output:
OTP of 6 length: rab0Tj
