How do you get a random number between two numbers in javascript?

TL;DR

function generateRandomInteger[min, max] {
  return Math.floor[min + Math.random[]*[max - min + 1]]
}

To get the random number generateRandomInteger[-20, 20];

EXPLANATION BELOW

integer - A number which is not a fraction; a whole number

We need to get a random number , say X between min and max. X, min and max are all integers

i.e min