text: function solve() {
      let input = document.getElementById("input");
      let result = document.getElementById("result");
      let selectMenuTo = document.getElementById("selectMenuTo");
      let optionBinary = document.createElement("option");
      optionBinary.value = "binary";
      optionBinary.innerHTML = "Binary";
      let optionHexadecimal = document.createElement("option");
      optionHexadecimal.value = "hexadecimal";
      optionHexadecimal.innerHTML = "Hexadecimal";
      selectMenuTo.appendChild(optionBinary);
      selectMenuTo.appendChild(optionHexadecimal);
  
      document
          .getElementsByTagName("button")[0]
          .addEventListener("click", calculate);
  
      function calculate() {
          if (selectMenuTo.value === "binary") {
              result.value = Number(input.value).toString(2);
          } else if (selectMenuTo.value === "hexadecimal") {
              result.value = Number(input.value).toString(16).toUpperCase();
          }
      }
  }
  