Question

see http://jsfiddle.net/JPxXp/

I understand as to why I keep getting 1 as the minimum ball number; do I create another variable / array that holds the 6 randomised numbers (if so, how – I don’t fully understand how to do this).

Answer 1

First, define an array that holds the randomised numbers:

var random_balls = [];

Each time you generate a random number, add it to that array:

// generate, the + is to convert a string like '12' to the number 12, otherwise
// comparing them gives wrong results: '12' < '9' but 12 > 9
var random_ball = +balls[Math.floor(Math.random()*balls.length)];

// if indexOf returns -1, the ball is not present in the array
// (otherwise it returns the index at which the ball is)
while(random_balls.indexOf(random_ball) !== -1) {
    // generate again if you already took this ball
    random_ball = +balls[Math.floor(Math.random()*balls.length)];
}

// add to array
random_balls.push(random_ball);

// display
document.write(random_ball);

The min checker would iterate the new array with random numbers like this:

for (i=0; i<random_balls.length; i++)
{   if (random_balls[i] < min)
        min = random_balls[i];
}

In case you didn’t know, you can also use:

var min = Math.min.apply(null, random_balls); // use built in min function, passing array as arguments

http://jsfiddle.net/pimvdb/JPxXp/7/