CODEWITHSUNDEEP
javascriptjqueryhtmlarraysjquery-events
EliteKnight
EliteKnight

Reputation: 87

Populate one dropdown list based on another dropdown list

I have two dropdown menus as follows:

<form id="dynamicForm">
  <select id="A">

  </select>
  <select id="B">

  </select>
</form>

And I have a dictionary object where the keys are the options for A and the values, B are arrays corresponding to each element in A, as follows:

var diction = {
    A1: ["B1", "B2", "B3"], 
    A2: ["B4", "B5", "B6"]
}

How can I dynamically populate the menu B based on what the user selects in menu A?

Upvotes: 4

Views: 10024

Answers (3)

Pranav C Balan
Pranav C Balan

Reputation: 115282

Bind a change event handler and populate second select tag based on selected value.

var diction = {
  A1: ["B1", "B2", "B3"],
  A2: ["B4", "B5", "B6"]
}

// bind change event handler
$('#A').change(function() {
  // get the second dropdown
  $('#B').html(
      // get array by the selected value
      diction[this.value]
      // iterate  and generate options
      .map(function(v) {
        // generate options with the array element
        return $('<option/>', {
          value: v,
          text: v
        })
      })
    )
    // trigger change event to generate second select tag initially
}).change()
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form id="dynamicForm">
  <select id="A">
    <option value="A1">A1</option>
    <option value="A2">A2</option>
  </select>
  <select id="B">
  </select>
</form>

Upvotes: 4

ibrahim mahrir
ibrahim mahrir

Reputation: 31712

This will dynamically populate both selects:

var diction = {
  A1: ["B1", "B2", "B3"],
  A2: ["B4", "B5", "B6"]
};

// the function that will populate the select
function populateSelect(id, values) {
  // get the select element
  var $select = $(id);
  // empty it
  $select.empty();
  // for each value in values ...
  values.forEach(function(value) {
    // create an option element
    var $option = $("<option value='" + value + "'>" + value + "</option>");
    // and append it to the select
    $select.append($option);
  });
}

// when the #A select changes ...
$("#A").on("change", function() {
  // get the value of the selected element (the key)
  var key = $(this).val();
  // populate #B accordingly
  populateSelect("#B", diction[key]);
});

// Before anything, populate #A with the keys of diction and ...
populateSelect("#A", Object.keys(diction));
// ... #B with whatever #A hold its key 
populateSelect("#B", diction[$("#A").val()]);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form id="dynamicForm">
  <select id="A">

  </select>
  <select id="B">

  </select>
</form>

Upvotes: 2

kukkuz
kukkuz

Reputation: 42370

You can create a change listener for the first select box and populate the html of the second select box.

See demo below:

var diction = {
  A1: ["B1", "B2", "B3"],
  A2: ["B4", "B5", "B6"]
}
$('#A').on('change', function() {
  $('#B').html(
    diction[$(this).val()].reduce(function(p, c) {
      return p.concat('<option value="' + c + '">' + c + '</option>');
    }, '')
  );
}).trigger('change');
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<form id="dynamicForm">
  <select id="A">
    <option value="A1">A1</option>
    <option value="A2">A2</option>
  </select>
  <select id="B">

  </select>
</form>

Upvotes: 3

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