Random number generator without dupes in Javascript?

Question

I need help with writing some code that will create a random number from an array of 12 numbers and print it 9 times without dupes. This has been tough for me to accomplish.

Answer 1

Try this once:

//Here o is the array;
var testArr = [6, 7, 12, 15, 17, 20, 21];
    shuffle = function(o){ //v1.0
                        for(var j, x, i = o.length; i; j = parseInt(Math.random() * i), x = o[--i], o[i] = o[j], o[j] = x);
                        return o;
                };
shuffle(testArr);