Creating a random number inside a range in JavaScript

To generate a random number in the JavaScript, you can just use default random method on Math object:


The above code will generate some random number between 0 and 1 (inclusive of 0, but not 1).

If you only want an integer out of the random method, use the floor method of Math object


But the above code will generate single integer, that's 0.

Generate a random number between 0 and 9(both inclusive)

As you know Math.random() will give you a number between 0 and 0.999999... So multiplying it with 10 will give a number between 0 and 9.99999.... Then use Math.floor to convert the obtained number to integer i.e., the following code will give you any of the 10 integers from 0 to 9


Generate random number between 1 and 10

From the above code it's obvious that you can add 1 to it to generate a random number between 1 and 10.

// or

Similarly Math.floor(Math.random()*500)+1 will give you a number between 1 and 500

Use Math.ceil() to even simplify the expression:

Math.ceil(Math.random() * 10)

If you use Math.round(Math.random() * 10), you will get any integer between 0 and 10, including both 0 and 10. So you can get any number out of 11 possible integers, if you use Math.round.

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