Use the basic Math methods:

• Math.random() returns a random number between 0 and 1 (including 0, excluding 1).


• Multiply this number by the highest desired number (e.g. 10)



• Round this number downward to its nearest integer

  
  
  

  Math.floor(Math.random()*10) + 1
  
  

Example:

//Example, including customisable intervals [lower_bound, upper_bound)

var limit = 10,

    amount = 3,

    lower_bound = 1,

    upper_bound = 10,

    unique_random_numbers = [];



if (amount > limit) limit = amount; //Infinite loop if you want more unique

                                    //Natural numbers than exist in a

                                    // given range

while (unique_random_numbers.length < limit) {

    var random_number = Math.floor(Math.random()*(upper_bound - lower_bound) + lower_bound);

    if (unique_random_numbers.indexOf(random_number) == -1) { 

        // Yay! new random number

        unique_random_numbers.push( random_number );

    }

}

// unique_random_numbers is an array containing 3 unique numbers in the given range