Get Random Number with JavaScript

To get a random number between two numbers using JavaScript, you can use a simple function that uses two useful math methods: Math.floor and Math.random().

Math.random() by itself will generate a pseudo-random decimal number between 0 and 1, inclusive of 0 but not inclusive of 1.

console.log(Math.random()); // 0.44914744650214833
Code language: JavaScript (javascript)

In most cases, this isn’t what you want, so you can build a utility function to generate a random integer between two numbers with JavaScript, like the following:

function RandomInteger (min, max) {
  return Math.floor(Math.random() * (max - min + 1) + min);
}

console.log(RandomInteger(1, 30));
Code language: JavaScript (javascript)

The above code is incorporated into the following interactive CodePen demo. In the demo you can select min and max values then use the button to generate a whole number between the two values, inclusive.

As mentioned, this works, however, the “random” numbers generated are not genuinely random. Thus, you should not use this to generate numbers that are important for app security, passwords, etc.