Accessibility in React Combo box component
26 Jan 202418 minutes to read
The ComboBox 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.
The ComboBox component followed the accessibility guidelines and standards, including ADA, Section 508, WCAG 2.2 standards, and WCAG roles that are commonly used to evaluate accessibility.
The accessibility compliance for the ComboBox component is outlined below.
- All features of the component meet the requirement.
- Some features of the component do not meet the requirement.
- The component does not meet the requirement.WAI-ARIA attributes
The ComboBox component followed the WAI-ARIA patterns to meet the accessibility. The following ARIA attributes are used in the ComboBox component:
| Properties | Functionalities |
|---|---|
| aria-haspopup | Indicates whether the ComboBox 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 ComboBox element. |
| aria-disabled | Indicates whether the ComboBox 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. |
| aria-autocomplete | This attribute contains the ‘both’ to a list of options shows and the currently selected suggestion also shows inline. |
Keyboard interaction
You can use the following key shortcuts to access the ComboBox without interruptions.
| Keyboard shortcuts | Actions |
|---|---|
| Arrow Down | Selects the first item in the ComboBox 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 popup list closes when it is in open state. |
| 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 | Open the popup list |
| Alt + Up | Close 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 | Cursor moves to before of first character in input |
| End | Cursor moves to next of last character in input |
In the below sample, alt+t keys are used to focus the ComboBox component.
[Class-component]
import { ComboBoxComponent } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';
export default class App extends React.Component {
// defined the array of data
gameList = [
{ Id: 'Game2', Game: 'Badminton' },
{ Id: 'Game3', Game: 'Basketball' },
{ Id: 'Game4', Game: 'Cricket' },
{ Id: 'Game5', Game: 'Football' },
{ Id: 'Game6', Game: 'Golf' },
{ Id: 'Game7', Game: 'Hockey' },
{ Id: 'Game8', Game: 'Rugby' },
{ Id: 'Game9', Game: 'Snooker' },
{ Id: 'Game10', Game: 'Tennis' },
];
// maps the appropriate column to fields property
fields = { text: 'Game', value: 'Id' };
// instance of ComboBox component
comboBoxObj;
componentDidMount() {
const proxy = this;
document.onkeyup = (e) => {
if (e.altKey && e.keyCode === 84 /* t */) {
// press alt+t to focus the control.
proxy.comboBoxObj.inputElement.focus();
}
};
}
render() {
return (
// specifies the tag for render the ComboBox component
<ComboBoxComponent id="comboelement" ref={(scope) => { this.comboBoxObj = scope; }} popupHeight='200px' fields={this.fields} dataSource={this.gameList} placeholder="Select a game"/>);
}
}
ReactDOM.render(<App />, document.getElementById('sample'));import { ComboBoxComponent } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';
export default class App extends React.Component<{}, {}> {
// defined the array of data
private gameList: { [key: string]: Object }[] = [
{ Id: 'Game2', Game: 'Badminton' },
{ Id: 'Game3', Game: 'Basketball' },
{ Id: 'Game4', Game: 'Cricket' },
{ Id: 'Game5', Game: 'Football' },
{ Id: 'Game6', Game: 'Golf' },
{ Id: 'Game7', Game: 'Hockey' },
{ Id: 'Game8', Game: 'Rugby' },
{ Id: 'Game9', Game: 'Snooker' },
{ Id: 'Game10', Game: 'Tennis' },
];
// maps the appropriate column to fields property
private fields: object = { text: 'Game', value: 'Id' };
// instance of ComboBox component
private comboBoxObj: ComboBoxComponent;
public componentDidMount() {
const proxy = this;
document.onkeyup = (e) => {
if (e.altKey && e.keyCode === 84 /* t */) {
// press alt+t to focus the control.
(proxy.comboBoxObj as any).inputElement.focus();
}
};
}
public render() {
return (
// specifies the tag for render the ComboBox component
<ComboBoxComponent id="comboelement" ref={(scope) => { (this.comboBoxObj as ComboBoxComponent | null) = scope; }} popupHeight='200px' fields={this.fields} dataSource={this.gameList} placeholder="Select a game" />
);
}
}
ReactDOM.render(<App />, document.getElementById('sample'));[Functional-component]
import { ComboBoxComponent } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';
function App() {
// defined the array of data
const gameList = [
{ Id: 'Game2', Game: 'Badminton' },
{ Id: 'Game3', Game: 'Basketball' },
{ Id: 'Game4', Game: 'Cricket' },
{ Id: 'Game5', Game: 'Football' },
{ Id: 'Game6', Game: 'Golf' },
{ Id: 'Game7', Game: 'Hockey' },
{ Id: 'Game8', Game: 'Rugby' },
{ Id: 'Game9', Game: 'Snooker' },
{ Id: 'Game10', Game: 'Tennis' },
];
// maps the appropriate column to fields property
const fields = { text: 'Game', value: 'Id' };
// instance of ComboBox component
let comboBoxObj;
React.useEffect(() => {
const proxy = this;
document.onkeyup = (e) => {
if (e.altKey && e.keyCode === 84 /* t */) {
// press alt+t to focus the control.
proxy.comboBoxObj.inputElement.focus();
}
};
}, []);
return (
// specifies the tag for render the ComboBox component
<ComboBoxComponent id="comboelement" ref={(scope) => { comboBoxObj = scope; }} popupHeight='200px' fields={fields} dataSource={gameList} placeholder="Select a game"/>);
}
ReactDOM.render(<App />, document.getElementById('sample'));import { ComboBoxComponent } from '@syncfusion/ej2-react-dropdowns';
import * as React from 'react';
import * as ReactDOM from 'react-dom';
function App() {
// defined the array of data
const gameList: { [key: string]: Object }[] = [
{ Id: 'Game2', Game: 'Badminton' },
{ Id: 'Game3', Game: 'Basketball' },
{ Id: 'Game4', Game: 'Cricket' },
{ Id: 'Game5', Game: 'Football' },
{ Id: 'Game6', Game: 'Golf' },
{ Id: 'Game7', Game: 'Hockey' },
{ Id: 'Game8', Game: 'Rugby' },
{ Id: 'Game9', Game: 'Snooker' },
{ Id: 'Game10', Game: 'Tennis' },
];
// maps the appropriate column to fields property
const fields: object = { text: 'Game', value: 'Id' };
// instance of ComboBox component
let comboBoxObj: ComboBoxComponent;
React.useEffect(() => {
const proxy = this;
document.onkeyup = (e) => {
if (e.altKey && e.keyCode === 84 /* t */) {
// press alt+t to focus the control.
(proxy.comboBoxObj as any).inputElement.focus();
}
};
}, []);
return (
// specifies the tag for render the ComboBox component
<ComboBoxComponent id="comboelement" ref={(scope) => { (comboBoxObj as ComboBoxComponent | null) = scope; }} popupHeight='200px' fields={fields} dataSource={gameList} placeholder="Select a game" />
);
}
ReactDOM.render(<App />, document.getElementById('sample'));Ensuring accessibility
The ComboBox component’s accessibility levels are ensured through an accessibility-checker and axe-core software tools during automated testing.
The accessibility compliance of the ComboBox component is shown in the following sample. Open the sample in a new window to evaluate the accessibility of the ComboBox component with accessibility tools.