function solve() {
    let options = document.getElementById("selectMenuTo");
    let binaryOption = document.createElement("option");
    binaryOption.textContent = "binary";
    options.appendChild(binaryOption);
    let hexOption = document.createElement("option");
    hexOption.textContent = "hexadecimal";
    options.appendChild(hexOption);

    function convert() {
        let input = Number(document.getElementById("input").value);
        let result;
        if (options.value.toLowerCase() === "binary") {
            result = input.toString(2);
        } else if (options.value.toLowerCase() === "hexadecimal") {
            result = input.toString(16).toUpperCase();
        }
        document.getElementById("result").value = result;
    }

    document.querySelector("#container > button").addEventListener('click', convert);
}