1Math.random() 
2// will return a number between 0 and 1, you can then time it up to get larger numbers.
3//When using bigger numbers remember to use Math.floor if you want it to be a integer
4Math.floor(Math.random() * 10) // Will return a integer between 0 and 9
5Math.floor(Math.random() * 11) // Will return a integer between 0 and 10
6
7// You can make functions aswell 
8function randomNum(min, max) {
9	return Math.floor(Math.random() * (max - min)) + min; // You can remove the Math.floor if you don't want it to be an integer
10}

1function getRandomNumberBetween(min,max){
2    return Math.floor(Math.random()*(max-min+1)+min);
3}
4
5//usage example: getRandomNumberBetween(20,400); 
6

1var random;
2var max = 8
3function findRandom() {
4  random = Math.floor(Math.random() * max) //Finds number between 0 - max
5  console.log(random)
6}
7findRandom()

1function randomNumber(min, max) {
2  return Math.floor(Math.random() * (max - min)) + min + 1;
3}

1/* 
2   The Math.random() function returns a floating-point, pseudo-random
3   number in the range 0 to less than 1 (inclusive of 0, but not 1)
4   with approximately uniform distribution over that range — which you
5   can then scale to your desired range. The implementation selects the
6   initial seed to the random number generation algorithm; it cannot
7   be chosen or reset by the user.
8*/
9function getRandomInt(max) {
10   return Math.floor(Math.random() * Math.floor(max));
11}
12
13console.log(getRandomInt(3));
14// expected output: 0, 1 or 2
15
16console.log(getRandomInt(1));
17// expected output: 0
18
19console.log(Math.random());
20// expected output: a number from 0 to <1

1//Returns a number between 1 and 0
2  console.log(Math.random());
3  
4//if you want a random number between two particular numbers, 
5//you can use this function
6  function getRandomBetween(min, max) {
7    return Math.random() * (max - min) + min;
8  }
9//Returns a random number between 20 and 170
10  console.log(getRandomBetween(20,170));
11  
12//if you want a random integer number from one number to another 
13//(including the min and the max numbers), you can use this function
14  function getRandomIntBetween(min, max) {
15    min = Math.ceil(min);
16    max = Math.floor(max);
17    return Math.floor(Math.random() * (max - min + 1)) + min;
18  }
19  
20//Returns a random integer number from 0 to 25
21  console.log(getRandomIntInclusive(0,25));