Dynamic linked selection

  1. Basic selection

  2. Segment Selection

  3. Category selection

The choice of one parameter affects the options available in another section, with subjects depending on segments. If a subject is selected, only assignments related to that specific subject will be displayed.

Answer №1

If you're looking to dynamically change content based on a dropdown selection, the onchange event is your go-to. Here's an example:

<select id="standardSelectId" onchange="fillSection(this)">...</select>
<select id="sectionSelectId" onchange="fillSubject(this)"><option>-- Select Standard first --</option></select>
<select id="subjectSelectId"><option>-- Select Section first --</option></select>

Next, create a JavaScript function to populate the subsequent select with options and reset any dependent selects:

<script type="text/javascript">
function fillSection(e) {
  var choice = e.options[e.selectedIndex];
  var sectionSelect = document.getElementById("sectionSelectId");
  var subjectSelect = document.getElementById("subjectSelectId");
  subjectSelect.options.length = 0;
  try { subjectSelect.add(new Option("-- Select Section first --", ""))} catch(ex) {subjectSelect.add(new Option("-- Select Section first --", ""), null)}
  sectionSelect.options.length = 0;
  switch (choice.value) {
    case <standard val1>:
      try { sectionSelect.add(new Option(section1_label_1, section1_key_1))} catch(ex) {subjectSelect.add(new Option(section1_label_1, section1_key_1), null)}
      ...
      try { sectionSelect.add(new Option(section1_label_N, section1_key_N))} catch(ex) {subjectSelect.add(new Option(section1_label_N, section1_key_N), null)}
      break;
    case <standard valX>:
      try { sectionSelect.add(new Option(sectionX_label_1, sectionX_key_1))} catch(ex) {subjectSelect.add(new Option(sectionX_label_1, sectionX_key_1), null)}
      ...
      try { sectionSelect.add(new Option(sectionX_label_N, sectionX_key_N))} catch(ex) {subjectSelect.add(new Option(sectionX_label_N, sectionX_key_N), null)}
      break;
  }
  function fillSubject(e) {
    ...
  }

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