在默认依赖项时重置选择选项

Question

我使用纯 js。我很难将选择框重置为默认值。正如您在下面的代码中看到的那样，我想让两个选择相互依赖。如果我选择这个，它只会显示这个，但是当我选择选项值 = 0 的第一个选择时重置时，我希望第二个选择也重置为默认值。

const faculties = {
  1: ["Magister Manajemen", "Magister Teologi"],
  2: ["Ilmu Filsafat"],
  3: ["Pendidikan Agama", "Pendidikan Bahasa Inggris", "Pendidikan Ekonomi", "Pendidikan Luar Sekolah"],
  4: ["Akuntansi", "Manejemen"],
  5: ["Agroteknologi"],
  6: ["Informatika", "Sistem Informasi"],
  7: ["Profesi Ners", "Keperawatan"],
  8: ["Sekretari D3"],
};

let facultySelection = document.querySelector("#faculty");
let prodiSelection = document.querySelector("#pStudy");

facultySelection.addEventListener("change", (event) => {
  let prodies = faculties[event.target.value];
  pStudy.innerHTML = prodies.map((p) => `<option value="${p}">${p}</option>`).join("");

  reset();
});

function reset() {
  if (prodiSelection.selected == 0) {
    pStudy.innerHTML = `<option value="0">-- SELECT PROGRAM STUDY --</option>`;
  }
}

<div class="mb-3">
  <label for="faculty">Faculty</label>
  <select class="form-select mt-2" id="faculty" name="faculty">
    <option value="0" selected="selected">--SELECT FACULTY --</option>
    <option value="1">Pascasarjana</option>
    <option value="2">Fakultas Filsafat</option>
    <option value="3">Fakultas Keguruan dan Ilmu Pendidikan</option>
    <option value="4">Fakultas Ekonomi dan Bisnis</option>
    <option value="5">Fakultas Pertanian</option>
    <option value="6">Fakultas Ilmu Komputer</option>
    <option value="7">Fakultas Keperawatan</option>
    <option value="8">Akademi Sekretari Manajemen Indonesia Klabat</option>
  </select>
</div>
<div class="mb-3">
  <label for="pStudy">Program of Study</label>
  <select class="form-select mt-2" id="pStudy" name="pStudy">
    <option value="0" selected>--SELECT PROGRAM OF STUDY --</option>
  </select>
</div>





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Answer 1

这能解决您的问题吗？您应该先检查 faculties 对象中是否存在所选值

const faculties = {
  1: ["Magister Manajemen", "Magister Teologi"],
  2: ["Ilmu Filsafat"],
  3: ["Pendidikan Agama", "Pendidikan Bahasa Inggris", "Pendidikan Ekonomi", "Pendidikan Luar Sekolah"],
  4: ["Akuntansi", "Manejemen"],
  5: ["Agroteknologi"],
  6: ["Informatika", "Sistem Informasi"],
  7: ["Profesi Ners", "Keperawatan"],
  8: ["Sekretari D3"],
};

let facultySelection = document.querySelector("#faculty");
let prodiSelection = document.querySelector("#pStudy");

facultySelection.addEventListener("change", (event) => {
  const val = event.target.value;

  if ( !val || !faculties[val] ) {
    pStudy.innerHTML = `<option value="0">-- SELECT PROGRAM STUDY --</option>`;
    return;
  } 

  let prodies = faculties[val];
  pStudy.innerHTML = prodies.map((p) => `<option value="${p}">${p}</option>`).join("");
});

<div class="mb-3">
  <label for="faculty">Faculty</label>
  <select class="form-select mt-2" id="faculty" name="faculty">
    <option value="0" selected="selected">--SELECT FACULTY --</option>
    <option value="1">Pascasarjana</option>
    <option value="2">Fakultas Filsafat</option>
    <option value="3">Fakultas Keguruan dan Ilmu Pendidikan</option>
    <option value="4">Fakultas Ekonomi dan Bisnis</option>
    <option value="5">Fakultas Pertanian</option>
    <option value="6">Fakultas Ilmu Komputer</option>
    <option value="7">Fakultas Keperawatan</option>
    <option value="8">Akademi Sekretari Manajemen Indonesia Klabat</option>
  </select>
</div>
<div class="mb-3">
  <label for="pStudy">Program of Study</label>
  <select class="form-select mt-2" id="pStudy" name="pStudy">
    <option value="0" selected>--SELECT PROGRAM OF STUDY --</option>
  </select>
</div>





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