var usedNum = new Array();

function getUniqueRandom(factor) {
    var num, index;
    var looking = true;
    do {
        num = Math.floor(Math.random() * factor)
        for (index = 0; index < usedNum.length; index++) {
            if (usedNum[index] == num) {
                break;
            }
        }
        if (index == usedNum.length) {
            usedNum[usedNum.length] = num;
            looking = false;
        }
    } while (looking);
    return num;
}

function generateNumber(lotto) {
   usedNum.length = 0;
   lotto.number1.value = getUniqueRandom(59) + 1;
   lotto.number2.value = getUniqueRandom(59) + 1;
   lotto.number3.value = getUniqueRandom(59) + 1;
   lotto.number4.value = getUniqueRandom(59) + 1;
   lotto.number5.value = getUniqueRandom(59) + 1;
   lotto.number6.value = Math.floor(Math.random() * 35) + 1
}