DevExtreme Accessibility Compliance
DevExtreme component libraries meet a variety of WCAG and Section 508 compliance standards. To assess this demo's accessibility level, click the Run AXE® Validation button to launch the AXE® web accessibility evaluation tool.
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The overall accessibility level of your application depends on the TextArea features used.
Backend API
import React, { useCallback, useState } from 'react';
import CheckBox from 'devextreme-react/check-box';
import type { CheckBoxTypes } from 'devextreme-react/check-box';
import SelectBox from 'devextreme-react/select-box';
import type { SelectBoxTypes } from 'devextreme-react/select-box';
import TextArea from 'devextreme-react/text-area';
import type { TextAreaTypes } from 'devextreme-react/text-area';
import { valueChangeEvents, content } from './data.ts';
const notesLabel = { 'aria-label': 'Notes' };
const eventLabel = { 'aria-label': 'Event' };
function App() {
const [value, setValue] = useState<string>(content);
const [valueForEditableTestArea, setValueForEditableTestArea] = useState<string>(content);
const [maxLength, setMaxLength] = useState<number | undefined>(undefined);
const [eventValue, setEventValue] = useState<string>(valueChangeEvents[0].name);
const [autoResizeEnabled, setAutoResizeEnabled] = useState<boolean>(false);
const [height, setHeight] = useState<number | undefined>(90);
const onCheckboxValueChanged = useCallback((e: CheckBoxTypes.ValueChangedEvent): void => {
const str = content;
setValue(e.value ? str.substring(0, 100) : str);
setMaxLength(e.value ? 100 : undefined);
}, []);
const onAutoResizeChanged = useCallback((e: CheckBoxTypes.ValueChangedEvent): void => {
setAutoResizeEnabled(e.value);
setHeight(e.value ? undefined : 90);
}, []);
const onSelectBoxValueChanged = useCallback((e: SelectBoxTypes.ValueChangedEvent): void => {
setEventValue(e.value);
}, []);
const onTextAreaValueChanged = useCallback((e: TextAreaTypes.ValueChangedEvent): void => {
setValueForEditableTestArea(e.value);
}, []);
return (
<>
<div className="dx-fieldset">
<div className="dx-fieldset-header">Default Mode</div>
<div className="dx-field">
<CheckBox
defaultValue={false}
onValueChanged={onCheckboxValueChanged}
text="Limit text length"
></CheckBox>
</div>
<div className="dx-field">
<CheckBox
value={autoResizeEnabled}
onValueChanged={onAutoResizeChanged}
text="Enable auto resize"
></CheckBox>
</div>
</div>
<div className="textarea-wrapper">
<TextArea
height={height}
maxLength={maxLength}
defaultValue={value}
inputAttr={notesLabel}
autoResizeEnabled={autoResizeEnabled}
/>
</div>
<div className="full-width-content">
<div className="dx-fieldset">
<div className="dx-fieldset-header">Event Handling and API</div>
<div className="dx-field">
<div className="dx-field-label">Synchronize text areas </div>
<div className="dx-field-value">
<SelectBox
items={valueChangeEvents}
valueExpr="name"
displayExpr="title"
inputAttr={eventLabel}
value={eventValue}
onValueChanged={onSelectBoxValueChanged}
/>
</div>
</div>
</div>
<div className="textarea-wrapper">
<TextArea
height={90}
value={valueForEditableTestArea}
valueChangeEvent={eventValue}
inputAttr={notesLabel}
onValueChanged={onTextAreaValueChanged}
/>
<TextArea
height={90}
value={valueForEditableTestArea}
readOnly={true}
inputAttr={notesLabel}
valueChangeEvent={eventValue}
/>
</div>
</div>
</>
);
}
export default App;
import React, { useCallback, useState } from 'react';
import CheckBox from 'devextreme-react/check-box';
import SelectBox from 'devextreme-react/select-box';
import TextArea from 'devextreme-react/text-area';
import { valueChangeEvents, content } from './data.js';
const notesLabel = { 'aria-label': 'Notes' };
const eventLabel = { 'aria-label': 'Event' };
function App() {
const [value, setValue] = useState(content);
const [valueForEditableTestArea, setValueForEditableTestArea] = useState(content);
const [maxLength, setMaxLength] = useState(undefined);
const [eventValue, setEventValue] = useState(valueChangeEvents[0].name);
const [autoResizeEnabled, setAutoResizeEnabled] = useState(false);
const [height, setHeight] = useState(90);
const onCheckboxValueChanged = useCallback((e) => {
const str = content;
setValue(e.value ? str.substring(0, 100) : str);
setMaxLength(e.value ? 100 : undefined);
}, []);
const onAutoResizeChanged = useCallback((e) => {
setAutoResizeEnabled(e.value);
setHeight(e.value ? undefined : 90);
}, []);
const onSelectBoxValueChanged = useCallback((e) => {
setEventValue(e.value);
}, []);
const onTextAreaValueChanged = useCallback((e) => {
setValueForEditableTestArea(e.value);
}, []);
return (
<>
<div className="dx-fieldset">
<div className="dx-fieldset-header">Default Mode</div>
<div className="dx-field">
<CheckBox
defaultValue={false}
onValueChanged={onCheckboxValueChanged}
text="Limit text length"
></CheckBox>
</div>
<div className="dx-field">
<CheckBox
value={autoResizeEnabled}
onValueChanged={onAutoResizeChanged}
text="Enable auto resize"
></CheckBox>
</div>
</div>
<div className="textarea-wrapper">
<TextArea
height={height}
maxLength={maxLength}
defaultValue={value}
inputAttr={notesLabel}
autoResizeEnabled={autoResizeEnabled}
/>
</div>
<div className="full-width-content">
<div className="dx-fieldset">
<div className="dx-fieldset-header">Event Handling and API</div>
<div className="dx-field">
<div className="dx-field-label">Synchronize text areas </div>
<div className="dx-field-value">
<SelectBox
items={valueChangeEvents}
valueExpr="name"
displayExpr="title"
inputAttr={eventLabel}
value={eventValue}
onValueChanged={onSelectBoxValueChanged}
/>
</div>
</div>
</div>
<div className="textarea-wrapper">
<TextArea
height={90}
value={valueForEditableTestArea}
valueChangeEvent={eventValue}
inputAttr={notesLabel}
onValueChanged={onTextAreaValueChanged}
/>
<TextArea
height={90}
value={valueForEditableTestArea}
readOnly={true}
inputAttr={notesLabel}
valueChangeEvent={eventValue}
/>
</div>
</div>
</>
);
}
export default App;
import React from 'react';
import ReactDOM from 'react-dom';
import App from './App.tsx';
ReactDOM.render(<App />, document.getElementById('app'));
import type { ValueChangeEvent } from './types.ts';
export const valueChangeEvents: ValueChangeEvent[] = [{
title: 'On Change',
name: 'change',
}, {
title: 'On Key Up',
name: 'keyup',
}];
export const content = 'Prepare 2013 Marketing Plan: We need to double revenues in 2013 and our marketing strategy is going to be key here. R&D is improving existing products and creating new products so we can deliver great AV equipment to our customers.Robert, please make certain to create a PowerPoint presentation for the members of the executive team.';
export type ValueChangeEvent = {
title: string;
name: string;
};
import React from 'react';
import ReactDOM from 'react-dom';
import App from './App.js';
ReactDOM.render(<App />, document.getElementById('app'));
export const valueChangeEvents = [
{
title: 'On Change',
name: 'change',
},
{
title: 'On Key Up',
name: 'keyup',
},
];
export const content =
'Prepare 2013 Marketing Plan: We need to double revenues in 2013 and our marketing strategy is going to be key here. R&D is improving existing products and creating new products so we can deliver great AV equipment to our customers.Robert, please make certain to create a PowerPoint presentation for the members of the executive team.';
<!DOCTYPE html>
<html lang="en">
<head>
<title>DevExtreme Demo</title>
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=5.0" />
<link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/26.1.5/css/dx.light.css" />
<link rel="stylesheet" type="text/css" href="./bundle.css" />
</head>
<body class="dx-viewport">
<div class="demo-container">
<div id="app"></div>
</div>
<script src="bundles/vendor/react.vendor.js"></script>
<script src="./bundle.js"></script>
</body>
</html>
.full-width-content {
width: 100%;
margin-top: 30px;
}
.full-width-content .textarea-wrapper > .dx-widget {
margin-bottom: 20px;
}
.full-width-content .dx-field {
max-width: 385px;
}
.textarea-wrapper {
padding: 0 20px;
}
You can also specify the maxLength property to limit the number of characters a user can enter. Note that this property only limits the number of characters for users. You can enter text that exceeds the maximum character length programmatically, but the number of characters displayed to users will still be limited by this property setting.
The TextArea stores the text in the value property and updates it after the DOM event occurs. To specify which DOM event to use instead of the default "change" event, use the valueChangeEvent property. To handle the value change, use the TextArea's onValueChanged function.
Change the text in the Event Handling and API section below to see how this feature works. Use the "Synchronize text areas" drop-down menu to select which event updates the read-only component's value: "change" or "keyup".