function generateLotto() {

    let result = "";

    // 6세트 생성
    for (let i = 1; i <= 6; i++) {

        let numbers = [];

        while (numbers.length < 6) {
            let num = Math.floor(Math.random() * 45) + 1;

            if (!numbers.includes(num)) {
                numbers.push(num);
            }
        }

        numbers.sort((a, b) => a - b);

        result += `<h3>${i}세트</h3>`;

        for (let n of numbers) {
            result += `<div class="ball">${n}</div>`;
        }

        result += "<br><br>";
    }

    document.getElementById("numbers").innerHTML = result;
}