Random Number Generator

Math.random()

It is the Math.random() function returns an unspecified floating-point number within the range of 0 to not more than one (inclusive of 0 but not exactly 1) with an approximately uniform distribution across that range . You can then adjust to your desired range. The implementation selects the initial seed to the random number generation algorithm; it cannot be chosen or reset by the user.https://interactive-examples.mdn.mozilla.net/pages/js/math-random.html

Notice: Math.random() does not offer cryptographically secure random numbers. Don't use them for any security-related purpose. Use the Web Crypto API instead, and more precisely the window.crypto.getRandomValues() method.

Syntax

Math.random()

Copy to Clipboard

Value of return

A floating-point or the pseudo random number between 1 (inclusive) as well as 1. (exclusive).

Examples

Note that as numbers in JavaScript are IEEE 754 floating point numbers with round-to-nearest-even behavior, the ranges claimed for the functions below (excluding the one for Math.random() itself) aren't exact. If very large limits are selected (2^53 or greater) is it possible in very uncommon cases to determine the upper bound that is usually excluded.

Finding an random number between 0 (inclusive) and 1 (exclusive)

function getRandom()  return Math.random();  

Copy to Clipboard

Finding an random number between two values

This example will return an random number between the specified values. The value returned is not less than (and could be equal to) min, and is lower than (and not the same as) max.

function getRandomArbitrary(min, max)  return Math.random() * (max - min) + min;  

Copy to Clipboard

Finding a random integer that is between two values

This example will return an undetermined integer that is between the values specified. The result is not lower than min (or the next number higher that min in the event that min isn't an integer) and is lower than (but not greater than) max.

function getRandomInt(min, max)  min = Math.ceil(min); max = Math.floor(max); return Math.floor(Math.random() * (max - min) + min); //The maximum is exclusive and the minimum is inclusive  

Copy to Clipboard

NOTE: It might be tempting to utilize Math.round() to achieve this, however doing this will result in the random numbers to have a different distribution, which might not be suitable for your requirements.

Finding a random integer that is between two values, inclusive

Although the function above, the getRandomInt() function above is inclusive at the minimum, it's not inclusive at the highest. What happens if you want your results be included both at the minimum and maximum? The getRandomIntInclusive() function below accomplishes that.

function getRandomIntInclusive(min, max)  min = Math.ceil(min); max = Math.floor(max); return Math.floor(Math.random() * (max - min + 1) + min); //The maximum is inclusive and the minimum is inclusive