Accessible combobox module


$ npm install combobo


In the browser

Just include combobo.js (window.Combobo will be set)

  <script src="./node_modules/combobo/dist/combobo.js"></script>
    var combobo = new Combobo();

CDN (unpkg)

<script src=""></script>

With browserify/webpack/any bundler

import Combobo from 'combobo'; // or require('combobo')

const combobo = new Combobo();


  • input (HTMLElement|String): The selector for the input (combobox) element or the input element reference.
    • Defaults to .combobox
  • list (HTMLElement|String): The selector for the list element or the list element reference.
    • Defaults to .listbox
  • options (Array|String): An array of HTMLElements or a string selector (to be qualified within the list element).
    • Defaults to .option
  • groups (Array|String): An array of HTMLElements or a string selector (to be qualified within the list element)
  • openClass (String): Class name that gets added when list is open.
    • Defaults to open
  • activeClass (String): Class name that gets added when active is triggered
    • Defaults to active
  • selectedClass (String): Class name that gets added when list item is selected
    • Defaults to selectedClass
  • allowEmpty (Boolean): If completely clear selection should be allowed (if field is required, false is probably what you want).
    • Defaults to true
  • useLiveRegion (Boolean): Determines whether or not to use Live Region (due to spotty AT support, aria-activedescendant will be used also). As of right now, it is recommended that you leave useLiveRegion on due to VoiceOver's lack of support for aria-activedescendant.
    • Defaults to true
  • multiselect (Boolean): Determines whether or not to enable multiselect features
    • Defaults to false
  • noResultsText (String): Sets text for when there are no matches
  • selectionValue (Function): A function that should return what the desired value of the input should be upon selection (this is especially useful for multiselect in that you can configure custom input values like {3 Items Selected}). An array of the selected options is passed as the one argument to the function.
  • optionValue (Function|String): A function that should return the desired markup of each option in the list (this allows for custom display of each option based on what is currently typed in the field) OR a string class that is to be added to the span that will be wrapped around the matched text in each option.
  • announcement (Object): An object containing the following properties:
    • count (Function): Announcement of currently selected items in list. The function accepts 1 argument which is the number of options selected.
      • Defaults to function (n) { return n + ' options available'; }
    • selected (String): The desired text to be used to inform AT that an option is selected (This is only applicable if useLiveRegion is true)
      • Defaults to "Selected."
    • groupChange (Function): The desired text to be announced when a group change occurs (as a result of arrow-key traversal of options). This is obviously only applicable if groups are used (see above for info on options.groups)
      • Example:
        function groupChangeHandler(newGroup) {
          var groupLabel = newGroup.querySelector('.optgroup-label').innerText;
          var len =
          ).filter(function (opt) {
            return !== 'none';
          return groupLabel + ' group entered, with ' + len + ' options.';
  • filter (String|Function): A filter-type string ('contains', 'starts-with', or 'equals') or a function that returns a array of filtered options.
    • Defaults to 'contains'
  • autoFilter (Boolean): To enable / disable filterng options on front end. If the developer wants to filter options from the server, then it should be false
    • Defaults to 'true'

Example Combobo call with options

var combobo = new Combobo({
  input: '.combobox',
  list: '.listbox',
  options: '.option', // qualified within `list`
  groups: null, // qualified within `list`
  openClass: 'open',
  activeClass: 'active',
  selectedClass: 'selected',
  useLiveRegion: true,
  multiselect: false,
  noResultsText: null,
  selectionValue: (selecteds) => => s.innerText.trim()).join(' - '),
  optionValue: 'underline', // wrap the matched portion of the option (if applicable) in a span with class "underline"
  announcement: {
    count: (n) => `${n} options available`,
    selected: 'Selected.'
  filter: 'contains' // 'starts-with', 'equals', or funk,
  autoFilter: true // 'true' or 'false' default true


Add an event listener with .on, remove event listener with .off (see example below)

  • list:open: Fires when the list is in an open state.
  • list:close: Fires when the list is in a closed state.
  • deselection: Fires when a selected element is deselected.
  • selection: Fires when an item in the list is selected.
  • change: Fires each time an option is made active (either through arrow key traversal or hover).
var combobo = new Combobo();

  .on('change', function () {
    console.log('stuff has changed and stuff');
  .on('selection', function () {
    console.log('selection made!');


  • goTo: accepts 1 argument which is either a String ('prev' or 'next'), which as it sounds will navigate Combobo to the previous or next option, or the index (Number) of the option to be traversed to. NOTE: This method does not select the option but rather highlights it as if the option is hovered or arrowed to.
  • select: selects the currently highlighted option
  • getOptIndex: returns the index (within the currently visible options) of the currently selected option.
  • reset: clears the filters and deselects any currently selected options.
  • setOptions: accepts 1 argument which is HTML code in String format. Adds one option to the existing dropdown list.
  • setNoResultFound: shows the No results found in dropdown if the matching options not available
  • emptyDropdownList: Empty the options in the dropdown list
  • updateSelectedOptions: Empty all the options and update with selected options in the list
  • setCurrentOptions: Sets the current Option from the current options list

Example usage

// move 5 options forward and select the option
  .goTo(combobo.getOptIndex() + 5)

// adds an option to the dropdown list
  .setOptions(`<li>Some Option</li>`);