(function() {

    var btn = document.querySelector("#getNumbers"),
        output = document.querySelector("#showNumbers");

    function getRandom(min, max) {

        return Math.round(Math.random() * (max - min) + min);

    }

    function showRandomNumbers() {

        var numbers = [],
            random;

        for(var i = 0; i < 6; i++) {
            random = getRandom(1, 49);

            while(numbers.indexOf(random) !== -1) {
                random = getRandom(1, 49);
                console.log("Powtórzyła się liczba " + random);
            }

            numbers.push(random);

        }

        output.value = numbers.join(", ");

    }

    btn.onclick = showRandomNumbers;

})();