Chips Combobox
A quick way to add or remove chips
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A quick way to add or remove chips
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The chips-combobox is a composite component that combines and implements combobox and chip. It is responsible for creating and managing chip components. It allows the searching of existing selection options and manages additions/removals of chips. The search/selection follows the combobox pattern.
combobox: the pattern as a whole, comprised of the following distinct parts
textbox: stores and displays the form value
flyout: the overlay that contains a listbox
listbox: listbox containing options
option/suggestion: a suggestion inside of the listbox and/or directly after the textbox value
autocomplete: the autocomplete type (optional)
filter: the filtering criteria (optional)
chip: the individual items inside that can be added and removed
View a fully styled example in our eBay Skin CSS framework.
Since chips-combobox is a composite component and includes a combobox , it automatically inherits its pattern. For the sake of completion, here's that pattern quoted from its own page:
Each row in the list of options performs only a singular action: setting the value of the textbox. It is not possible, at the time of writing, to have additional actions per row, e.g. add, edit or delete.
The combobox listbox is not intended for storing or display kind of single-select or multi-select state. Again, the purpose of each option is to simply set the value of the textbox.
A combobox is an enhancement of textbox. Likewise, autocomplete is an enhancement of combobox. Suggestions provided will update dynamically based on user input. The suggested values may appear inline within the textbox, in a list, or both places at once.
Examples of autocomplete are the URL bar in browsers, and the main search field in search engines.
Since chips-combobox manages the addition and removal of chip(s) , they require some key elements. A chip can be static of interactive. Static chips are extremely simple and don't require much guidance. Here, we will only be looking at interactive chips. Here's the markup for each chip:
Each chip has a button inside that removes the chip from the chips-combobox . The chip__text needs an id that is used by the button via aria-describedby to link the button removal to the specific chip.
The close svg icon for each chip needs to have aria-hidden="true" since its function is conveyed by the button.
Since chips combobox is a composite component and includes a combobox , it automatically inherits its interaction design. Once again, here's that pattern quoted from its own page:
Keyboard
When the combobox receives focus, the listbox should expand to show all options.
With listbox expanded, pressing
DOWN-ARROWandUP-ARROWkeys must navigate through the list of options. The keyboard focus will appear to be in two places at the same time - the textbox and the listbox. In actual fact, keyboard focus always stays on the textbox. The aria-activedescendant property controls the pseudo-focus inside of the listbox.Pressing
SPACEBARmust always enter a blank space in the textbox.For a combobox with
autoSelect, changing the highlighted option will automatically fill the textbox with that option.For a combobox without
autoSelect, changing the highlighted option must not automatically fill the textbox;ENTERkey is required to manually select the option.Pressing
ENTERkey while an option is highlighted must collapse the listbox. For a combobox withautoSelectthe form will be submitted. For a combobox withoutautoSelectthe form must not be submitted.Pressing
ESCkey while an option is highlighted must collapse the listbox.For autocomplete type "list":
The listbox remains but the options change based on the custom filtering criteria.
With focus in the empty combobox, type any letter. Any suggestions that match the filter will appear as options in the listbox flyout.
For autocomplete type "inline":
The listbox is removed. The entire combobox value will update as the user types, with the suggested portion highlighted as a selection range.
For autocomplete type "both":
This section is under development.
Screen Reader
The screen reader will announce the input as "text edit", "combobox" or words to those effect, depending on level of ARIA support.
The screen reader will announce "expanded" or "collapsed", depending on level of ARIA support.
The screen reader will announce any additional programmatic description, depending on level of ARIA support.
The screen reader will announce the current value of the textbox.
Mouse and Touch
When the combobox receives focus, via click or tap, the listbox should expand to show all options.
Clicking or tapping an option will fill the textbox with that value and collapse the listbox without triggering a form submit.
In addition, there is interaction between the combobox and chip items.
As the user has gained focus of the textbox, the listbox will display to show all available options. As the user types, the listbox will be filtered to display only items meeting the criteria of the entered text. Consistent with a typical combobox, the user would then use the arrow keys to navigate to the item they'd like to add. Pressing ENTER when the indicator is on a specific item, will create a chip with that item. Utilizing a mouse, when the user clicks on any of the items in the listbox, a chip will be created for that item.
A custom chip can be created only with the keyboard. As the user types inside the textbox, at any given moment, pressing ENTER will create a chip with/for the text present in the textbox.
There may be a tendency to consider using a comma(,) to fire off the creation of a chip. The current guidance is to avoid doing so. Commas are too specific in usage on certain platforms and do not have as wide of an intuitive base of accepted usage patterns. Conversely, ENTER is a universally accepted pattern for submission of an entry.
Rest State
Open State
Filled State
Disabled State
Error State
Usage of the error state requires the addition of the field error state.
For the sake of comprehensive coverage, once again, the portions relevant to the combobox are quoted from its developer guide:
Textbox
We start with a label and textbox.
We have added our elements inside of a
.comboboxwrapper element. This wrapper acts as our module root and hook for CSS & JavaScript.Remember: the textbox does not yet have a role of combobox, it is added later with JavaScript.
A listbox element will be appended to this wrapper. It is up to you whether you wish to render this server-side or client-side. There are pros and cons to both approaches, which we will discuss below.
Listbox
The listbox may render on the server or the client. It is wise to put the listbox in a hidden state if rendering on the server. To do so, use the
hiddenattribute.Using JavaScript we now begin converting the textbox to a combobox, by adding
role=combobox. We also create the properties and state that connect the combobox to the listbox:The new attributes are
role,aria-expanded,autocompleteandaria-owns.Description
At the time of writing, screen readers don't do a good job of conveying the combobox role or how to interact with it. To solve this problem, we can add a description via
aria-roledescription.Now the screen reader announces the description whenever focus lands on the combobox.
If the number of options will change based on the value of the combobox (i.e. filtering occurs), the description should also make the user aware of this:
Keyboard and Screen Reader Navigation
Our elements are now in place, but how does a keyboard user navigate to the options? We cannot use TAB key because focus must stay on the combobox (so that user can type and enter their own value). As with most complex widgets, the answer lies in the arrow keys. Up and down arrow keys are the way to select our combobox options.
If focus must remain on the combobox, how then do we also have focus on the listbox options? The answer is that we don't. Focus always remains on the combobox and instead we have a kind of pseudo-focus on the options.
How does the screen reader know where this pseudo-focus is?
Active Descendant
We call the option with pseudo-focus the "active descendant". And guess what, there is an ARIA attribute for this called
aria-activedescendant. This attribute is placed on the combobox element. The attribute value is the ID of the currently active (pseudo-focussed) option. This allows assistive technology such as a screen reader to programmatically determineTo make all of this easier, we recommend using a plugin such as makeup-active-descendant. After your HTML structure is in place, simply initialise the plugin on the widget and up/down arrow keys will update the necessary states. Use CSS to style the active descendant in any way you like.
This section gives an overview of ARIA usage, within the context of this pattern.
role=combobox
This attribute changes the role of the text input from textbox to combobox. We recommend applying this attribute on the client-side with JavaScript.
aria-roledescription
Gives additional instructions on how to operate the combobox options.
role=listbox
The list of suggestions has a role of listbox.
role=option
Each listbox item has a role of option.
aria-owns
This property creates a programmatic hierarchy in the accessibility tree for the combobox and the listbox.
aria-expanded
Conveys the expanded state of the combobox.
aria-label
Provides the expand/collapse button with an accessible label, in the case where it has no visible text (i.e. an icon button). It also provides an accessible label for the chips-combobox unordered list:
aria-labeledby
In instances where a heading or label is provided before the chips-combobox, it can link to the element for its aria label:
