Jquery - First select element must determine option of another select

Vakindu
December 30, 2023
129 views
0 votes
2 Answers

I would like the choice of the first select element to determine the options of the next select element.

For example when someone chooses ‘Ug’ in the first select element, ONLY the options ‘A and B’ should be displayed in the next select element.

Likewise, when the option ‘Ke’ is chosen in the first select element, ONLY the options ‘C and D’ should be displayed in the next select element, ETC…

The current code doesn’t show any options in the second select once I click the first select element.

Could you please help me fix the issue with this code?

The code looks like below.

Thanks in advance!

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<select class="form-control-selector" id="countryselect" name="countryselect" required>
  <option class="select-option" value="" selected>- Choose Country</option>
  <option class="select-option" value="Ug">Ug</option>
  <option class="select-option" value="Ke">Ke</option>
  <option class="select-option" value="Rw">Rw</option>
  <option class="select-option" value="Tz">Tz</option>
  <option class="select-option" value="SA">SA</option>
</select>

<select class="form-control-selector" id="cityselect" name="cityselect" required>
  <option class="select-option" value="" selected>- Choose City </option>

  <option class="select-option" value="A">A</option>
  <option class="select-option" value="B">B</option>

  <option class="select-option" value="C">C</option>
  <option class="select-option" value="D">D</option>

  <option class="select-option" value="E">E</option>
  <option class="select-option" value="F">F</option>

  <option class="select-option" value="G">G</option>
  <option class="select-option" value="H">H</option>

  <option class="select-option" value="I">I</option>
  <option class="select-option" value="J">J</option>
</select>

<script>
    $("#countryselect").change(function(){
        var selectedOption = $("select option:selected").text();
        $("#cityselect").empty();
        for(var index=1;index<10;index++){
            if(index>=parseInt(selectedOption)){
                $("#cityselect").append($('<option></option>').html(index));
            }
        }
    });
</script>

Answers

This code checks the selected option in the first select element (#countryselect) and populates the second select element (#cityselect) accordingly. You can extend the if conditions for each country and add their corresponding city options. If there are many countries, you might consider using a switch statement or a more advanced data structure to map countries to cities.

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<select class="form-control-selector" id="countryselect" name="countryselect" required>
  <option class="select-option" value="" selected>- Choose Country</option>
  <option class="select-option" value="Ug">Ug</option>
  <option class="select-option" value="Ke">Ke</option>
  <option class="select-option" value="Rw">Rw</option>
  <option class="select-option" value="Tz">Tz</option>
  <option class="select-option" value="SA">SA</option>
</select>

<select class="form-control-selector" id="cityselect" name="cityselect" required>
  <option class="select-option" value="" selected>- Choose City </option>
</select>

<script>
    $("#countryselect").change(function(){
        var selectedOption = $(this).val();
        $("#cityselect").empty();
        
        if(selectedOption === "Ug"){
            $("#cityselect").append($('<option value="A">A</option>'));
            $("#cityselect").append($('<option value="B">B</option>'));
        } else if(selectedOption === "Ke"){
            $("#cityselect").append($('<option value="C">C</option>'));
            $("#cityselect").append($('<option value="D">D</option>'));
        } else if(selectedOption === "Rw"){
            // Add options for Rwanda
        } else if(selectedOption === "Tz"){
            // Add options for Tanzania
        } else if(selectedOption === "SA"){
            // Add options for South Africa
        }
    });
</script>

Instead of adding and removing options to the select element you can also enable/disable form fields. In this example each cityselect is in its own fieldset. All the fieldsets are initially disabled. When an option in the countryselect is selected the matching fieldset will be enabled.

It is not an issue to have more form fields with the same name. If a form field or fieldset is disable the form field(s) are not included in the submit event.

document.forms.form01.countryselect.addEventListener('change', e => {
  let form = e.target.form;
  [...form.elements]
    .filter(elm => elm.nodeName == 'FIELDSET')
    .forEach(elm => elm.disabled = true);
  form[e.target.value].disabled = false;
});

fieldset {
  border: none;
}

fieldset:disabled {
  display: none;
}

<form name="form01">
  <select class="form-control-selector" name="countryselect" required>
    <option class="select-option" value="" selected>- Choose Country</option>
    <option class="select-option" value="Ug">Ug</option>
    <option class="select-option" value="Ke">Ke</option>
    <option class="select-option" value="Rw">Rw</option>
    <option class="select-option" value="Tz">Tz</option>
    <option class="select-option" value="SA">SA</option>
  </select>
  <fieldset name="Ug" disabled>
    <select class="form-control-selector" name="cityselect" required>
      <option class="select-option" value="" selected>- Choose City </option>
      <option value="A">A</option>
      <option value="B">B</option>
    </select>
  </fieldset>
  <fieldset name="Ke" disabled>
    <select class="form-control-selector" name="cityselect" required>
      <option class="select-option" value="" selected>- Choose City </option>
      <option value="C">C</option>
      <option value="D">D</option>
    </select>
  </fieldset>
</form>

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Jquery – First select element must determine option of another select

Answers