Accessibility in EJ2 TypeScript Drop down list control

13 Dec 20247 minutes to read

The DropDownList component has been designed, keeping in mind the WAI-ARIA specifications, and applies the WAI-ARIA roles, states, and properties along with keyboard support. This component is characterized by complete keyboard interaction support and ARIA accessibility support that makes it easy for people who use assistive technologies (AT) or those who completely rely on keyboard navigation.

ARIA attributes

The DropDownList component uses the Listbox role, and each list item has an option role. The following ARIA attributes denote the DropDownList state.

Properties Functionalities
aria-haspopup Indicates whether the DropDownList input element has a popup list or not.
aria-expanded Indicates whether the popup list has expanded or not.
aria-selected Indicates the selected option.
aria-readonly Indicates the readonly state of the DropDownList element.
aria-disabled Indicates whether the DropDownList component is in a disabled state or not.
aria-activedescendent This attribute holds the ID of the active list item to focus its descendant child element.
aria-owns This attribute contains the ID of the popup list to indicate popup as a child element.

Keyboard interaction

You can use the following key shortcuts to access the DropDownList without interruptions.

Keyboard shortcuts Actions
Arrow Down Selects the first item in the DropDownList when no item selected. Otherwise, selects the item next to the currently selected item.
Arrow Up Selects the item previous to the currently selected one.
Page Down Scrolls down to the next page and selects the first item when popup list opens.
Page Up Scrolls up to the previous page and selects the first item when popup list opens.
Enter Selects the focused item, and when it is in an open state the popup list closes. Otherwise, toggles the popup list.
Tab Focuses on the next TabIndex element on the page when the popup is closed. Otherwise, closes the popup list and remains the focus of the component.
Shift + tab Focuses on the previous TabIndex element on the page when the popup is closed. Otherwise, closes the popup list and remains the focus of the component.
Alt + Down Opens the popup list.
Alt + Up Closes the popup list.
Esc(Escape) Closes the popup list when it is in an open state and the currently selected item remains the same.
Home Selects the first item.
End Selects the last item.

In the below sample, focus the DropDownList component using alt+t keys.

import { DropDownList } from '@syncfusion/ej2-dropdowns';

// defined the array of data
let gameList: { [key: string]: Object }[] = [
        { Id: 'Game1', Game: 'Badminton' },
        { Id: 'Game2', Game: 'Basketball' },
        { Id: 'Game3', Game: 'Cricket' },
        { Id: 'Game4', Game: 'Football' },
        { Id: 'Game5', Game: 'Golf' },
        { Id: 'Game6', Game: 'Hockey' },
        { Id: 'Game7', Game: 'Rugby' },
        { Id: 'Game8', Game: 'Snooker' },
        { Id: 'Game9', Game: 'Tennis' },
    ];

// initialize DropDownList component
let dropDownListObject: DropDownList = new DropDownList({
    //set the data to dataSource property
    dataSource: gameList,
    //map to colum to fields
    fields: { text: 'Game', value:'Id' },
    // set placeholder to DropDownList input element
    placeholder: "Select a game",
    // set the popup list height
    popupHeight: '200px'
});

// render initialized DropDownList
dropDownListObject.appendTo('#ddlelement');

document.onkeyup = function (e) {
if (e.altKey && e.keyCode === 84 /* t */) {
    // press alt+t to focus the control.
    dropDownListObject.focusIn();
}
};
<!DOCTYPE html>
<html lang="en">

<head>
    <title>Essential JS 2 DropDownList</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript UI Controls" />
    <meta name="author" content="Syncfusion" />
    <link href="styles.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/28.1.33/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/28.1.33/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/28.1.33/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>

<body>
    <div id='loader'>LOADING....</div>
    <div id='container' style="margin:0 auto; width:250px;">
        <input type="text" tabindex="1" id='ddlelement' />
    </div>
</body>

</html>