Common components (e.g. <div>)

• Reference
  • Common components (e.g. <div>)
  • ref callback function
  • React event object
  • AnimationEvent handler function
  • ClipboardEvent handler function
  • CompositionEvent handler function
  • DragEvent handler function
  • FocusEvent handler function
  • Event handler function
  • InputEvent handler function
  • KeyboardEvent handler function
  • MouseEvent handler function
  • PointerEvent handler function
  • TouchEvent handler function
  • TransitionEvent handler function
  • UIEvent handler function
  • WheelEvent handler function
• Usage
  • Applying CSS styles
  • Manipulating a DOM node with a ref
  • Dangerously setting the inner HTML
  • Handling mouse events
  • Handling pointer events
  • Handling focus events
  • Handling keyboard events

Reference

Common components (e.g. <div>)

<div className="wrapper">Some content</div>

See more examples below.

Props

These special React props are supported for all built-in components:

• children: A React node (an element, a string, a number, a portal, an empty node like null, undefined and booleans, or an array of other React nodes). Specifies the content inside the component. When you use JSX, you will usually specify the children prop implicitly by nesting tags like <div><span /></div>.

• dangerouslySetInnerHTML: An object of the form { __html: '<p>some html</p>' } with a raw HTML string inside. Overrides the innerHTML property of the DOM node and displays the passed HTML inside. This should be used with extreme caution! If the HTML inside isn’t trusted (for example, if it’s based on user data), you risk introducing an XSS vulnerability. Read more about using dangerouslySetInnerHTML.

• ref: A ref object from useRef or createRef, or a ref callback function, or a string for legacy refs. Your ref will be filled with the DOM element for this node. Read more about manipulating the DOM with refs.

• suppressContentEditableWarning: A boolean. If true, suppresses the warning that React shows for elements that both have children and contentEditable={true} (which normally do not work together). Use this if you’re building a text input library that manages the contentEditable content manually.

• suppressHydrationWarning: A boolean. If you use server rendering, normally there is a warning when the server and the client render different content. In some rare cases (like timestamps), it is very hard or impossible to guarantee an exact match. If you set suppressHydrationWarning to true, React will not warn you about mismatches in the attributes and the content of that element. It only works one level deep, and is intended to be used as an escape hatch. Don’t overuse it. Read about suppressing hydration errors.

• style: An object with CSS styles, for example { fontWeight: 'bold', margin: 20 }. Similarly to the DOM style property, the CSS property names need to be written as camelCase, for example fontWeight instead of font-weight. You can pass strings or numbers as values. If you pass a number, like width: 100, React will automatically append px (“pixels”) to the value unless it’s a unitless property. We recommend using style only for dynamic styles where you don’t know the style values ahead of time. In other cases, applying plain CSS classes with className is more efficient. Read more about className and style.

These standard DOM props are also supported for all built-in components:

• accessKey: A string. Specifies a keyboard shortcut for the element. Not generally recommended.
• aria-*: ARIA attributes let you specify the accessibility tree information for this element. See ARIA attributes for a complete reference. In React, all ARIA attribute names are exactly the same as in HTML.
• autoCapitalize: A string. Specifies whether and how the user input should be capitalized.
• className: A string. Specifies the element’s CSS class name. Read more about applying CSS styles.
• contentEditable: A boolean. If true, the browser lets the user edit the rendered element directly. This is used to implement rich text input libraries like Lexical. React warns if you try to pass React children to an element with contentEditable={true} because React will not be able to update its content after user edits.
• data-*: Data attributes let you attach some string data to the element, for example data-fruit="banana". In React, they are not commonly used because you would usually read data from props or state instead.
• dir: Either 'ltr' or 'rtl'. Specifies the text direction of the element.
• draggable: A boolean. Specifies whether the element is draggable. Part of HTML Drag and Drop API.
• enterKeyHint: A string. Specifies which action to present for the enter key on virtual keyboards.
• htmlFor: A string. For <label> and <output>, lets you associate the label with some control. Same as for HTML attribute. React uses the standard DOM property names (htmlFor) instead of HTML attribute names.
• hidden: A boolean or a string. Specifies whether the element should be hidden.
• id: A string. Specifies a unique identifier for this element, which can be used to find it later or connect it with other elements. Generate it with useId to avoid clashes between multiple instances of the same component.
• is: A string. If specified, the component will behave like a custom element.
• inputMode: A string. Specifies what kind of keyboard to display (for example, text, number or telephone).
• itemProp: A string. Specifies which property the element represents for structured data crawlers.
• lang: A string. Specifies the language of the element.
• onAnimationEnd: An AnimationEvent handler function. Fires when a CSS animation completes.
• onAnimationEndCapture: A version of onAnimationEnd that fires in the capture phase.
• onAnimationIteration: An AnimationEvent handler function. Fires when an iteration of a CSS animation ends, and another one begins.
• onAnimationIterationCapture: A version of onAnimationIteration that fires in the capture phase.
• onAnimationStart: An AnimationEvent handler function. Fires when a CSS animation starts.
• onAnimationStartCapture: onAnimationStart, but fires in the capture phase.
• onAuxClick: A MouseEvent handler function. Fires when a non-primary pointer button was clicked.
• onAuxClickCapture: A version of onAuxClick that fires in the capture phase.
• onBeforeInput: An InputEvent handler function. Fires before the value of an editable element is modified. React does not yet use the native beforeinput event, and instead attempts to polyfill it using other events.
• onBeforeInputCapture: A version of onBeforeInput that fires in the capture phase.
• onBlur: A FocusEvent handler function. Fires when an element lost focus. Unlike the built-in browser blur event, in React the onBlur event bubbles.
• onBlurCapture: A version of onBlur that fires in the capture phase.
• onClick: A MouseEvent handler function. Fires when the primary button was clicked on the pointing device.
• onClickCapture: A version of onClick that fires in the capture phase.
• onCompositionStart: A CompositionEvent handler function. Fires when an input method editor starts a new composition session.
• onCompositionStartCapture: A version of onCompositionStart that fires in the capture phase.
• onCompositionEnd: A CompositionEvent handler function. Fires when an input method editor completes or cancels a composition session.
• onCompositionEndCapture: A version of onCompositionEnd that fires in the capture phase.
• onCompositionUpdate: A CompositionEvent handler function. Fires when an input method editor receives a new character.
• onCompositionUpdateCapture: A version of onCompositionUpdate that fires in the capture phase.
• onContextMenu: A MouseEvent handler function. Fires when the user tries to open a context menu.
• onContextMenuCapture: A version of onContextMenu that fires in the capture phase.
• onCopy: A ClipboardEvent handler function. Fires when the user tries to copy something into the clipboard.
• onCopyCapture: A version of onCopy that fires in the capture phase.
• onCut: A ClipboardEvent handler function. Fires when the user tries to cut something into the clipboard.
• onCutCapture: A version of onCut that fires in the capture phase.
• onDoubleClick: A MouseEvent handler function. Fires when the user clicks twice. Corresponds to the browser dblclick event.
• onDoubleClickCapture: A version of onDoubleClick that fires in the capture phase.
• onDrag: A DragEvent handler function. Fires while the user is dragging something.
• onDragCapture: A version of onDrag that fires in the capture phase.
• onDragEnd: A DragEvent handler function. Fires when the user stops dragging something.
• onDragEndCapture: A version of onDragEnd that fires in the capture phase.
• onDragEnter: A DragEvent handler function. Fires when the dragged content enters a valid drop target.
• onDragEnterCapture: A version of onDragEnter that fires in the capture phase.
• onDragOver: A DragEvent handler function. Fires on a valid drop target while the dragged content is dragged over it. You must call e.preventDefault() here to allow dropping.
• onDragOverCapture: A version of onDragOver that fires in the capture phase.
• onDragStart: A DragEvent handler function. Fires when the user starts dragging an element.
• onDragStartCapture: A version of onDragStart that fires in the capture phase.
• onDrop: A DragEvent handler function. Fires when something is dropped on a valid drop target.
• onDropCapture: A version of onDrop that fires in the capture phase.
• onFocus: A FocusEvent handler function. Fires when an element receives focus. Unlike the built-in browser focus event, in React the onFocus event bubbles.
• onFocusCapture: A version of onFocus that fires in the capture phase.
• onGotPointerCapture: A PointerEvent handler function. Fires when an element programmatically captures a pointer.
• onGotPointerCaptureCapture: A version of onGotPointerCapture that fires in the capture phase.
• onKeyDown: A KeyboardEvent handler function. Fires when a key is pressed.
• onKeyDownCapture: A version of onKeyDown that fires in the capture phase.
• onKeyPress: A KeyboardEvent handler function. Deprecated. Use onKeyDown or onBeforeInput instead.
• onKeyPressCapture: A version of onKeyPress that fires in the capture phase.
• onKeyUp: A KeyboardEvent handler function. Fires when a key is released.
• onKeyUpCapture: A version of onKeyUp that fires in the capture phase.
• onLostPointerCapture: A PointerEvent handler function. Fires when an element stops capturing a pointer.
• onLostPointerCaptureCapture: A version of onLostPointerCapture that fires in the capture phase.
• onMouseDown: A MouseEvent handler function. Fires when the pointer is pressed down.
• onMouseDownCapture: A version of onMouseDown that fires in the capture phase.
• onMouseEnter: A MouseEvent handler function. Fires when the pointer moves inside an element. Does not have a capture phase. Instead, onMouseLeave and onMouseEnter propagate from the element being left to the one being entered.
• onMouseLeave: A MouseEvent handler function. Fires when the pointer moves outside an element. Does not have a capture phase. Instead, onMouseLeave and onMouseEnter propagate from the element being left to the one being entered.
• onMouseMove: A MouseEvent handler function. Fires when the pointer changes coordinates.
• onMouseMoveCapture: A version of onMouseMove that fires in the capture phase.
• onMouseOut: A MouseEvent handler function. Fires when the pointer moves outside an element, or if it moves into a child element.
• onMouseOutCapture: A version of onMouseOut that fires in the capture phase.
• onMouseUp: A MouseEvent handler function. Fires when the pointer is released.
• onMouseUpCapture: A version of onMouseUp that fires in the capture phase.
• onPointerCancel: A PointerEvent handler function. Fires when the browser cancels a pointer interaction.
• onPointerCancelCapture: A version of onPointerCancel that fires in the capture phase.
• onPointerDown: A PointerEvent handler function. Fires when a pointer becomes active.
• onPointerDownCapture: A version of onPointerDown that fires in the capture phase.
• onPointerEnter: A PointerEvent handler function. Fires when a pointer moves inside an element. Does not have a capture phase. Instead, onPointerLeave and onPointerEnter propagate from the element being left to the one being entered.
• onPointerLeave: A PointerEvent handler function. Fires when a pointer moves outside an element. Does not have a capture phase. Instead, onPointerLeave and onPointerEnter propagate from the element being left to the one being entered.
• onPointerMove: A PointerEvent handler function. Fires when a pointer changes coordinates.
• onPointerMoveCapture: A version of onPointerMove that fires in the capture phase.
• onPointerOut: A PointerEvent handler function. Fires when a pointer moves outside an element, if the pointer interaction is cancelled, and a few other reasons.
• onPointerOutCapture: A version of onPointerOut that fires in the capture phase.
• onPointerUp: A PointerEvent handler function. Fires when a pointer is no longer active.
• onPointerUpCapture: A version of onPointerUp that fires in the capture phase.
• onPaste: A ClipboardEvent handler function. Fires when the user tries to paste something from the clipboard.
• onPasteCapture: A version of onPaste that fires in the capture phase.
• onScroll: An Event handler function. Fires when an element has been scrolled. This event does not bubble.
• onScrollCapture: A version of onScroll that fires in the capture phase.
• onSelect: An Event handler function. Fires after the selection inside an editable element like an input changes. React extends the onSelect event to work for contentEditable={true} elements as well. In addition, React extends it to fire for empty selection and on edits (which may affect the selection).
• onSelectCapture: A version of onSelect that fires in the capture phase.
• onTouchCancel: A TouchEvent handler function. Fires when the browser cancels a touch interaction.
• onTouchCancelCapture: A version of onTouchCancel that fires in the capture phase.
• onTouchEnd: A TouchEvent handler function. Fires when one or more touch points are removed.
• onTouchEndCapture: A version of onTouchEnd that fires in the capture phase.
• onTouchMove: A TouchEvent handler function. Fires one or more touch points are moved.
• onTouchMoveCapture: A version of onTouchMove that fires in the capture phase.
• onTouchStart: A TouchEvent handler function. Fires when one or more touch points are placed.
• onTouchStartCapture: A version of onTouchStart that fires in the capture phase.
• onTransitionEnd: A TransitionEvent handler function. Fires when a CSS transition completes.
• onTransitionEndCapture: A version of onTransitionEnd that fires in the capture phase.
• onWheel: A WheelEvent handler function. Fires when the user rotates a wheel button.
• onWheelCapture: A version of onWheel that fires in the capture phase.
• role: A string. Specifies the element role explicitly for assistive technologies.
• slot: A string. Specifies the slot name when using shadow DOM. In React, an equivalent pattern is typically achieved by passing JSX as props, for example <Layout left={<Sidebar />} right={<Content />} />.
• spellCheck: A boolean or null. If explicitly set to true or false, enables or disables spellchecking.
• tabIndex: A number. Overrides the default Tab button behavior. Avoid using values other than -1 and 0.
• title: A string. Specifies the tooltip text for the element.
• translate: Either 'yes' or 'no'. Passing 'no' excludes the element content from being translated.

You can also pass custom attributes as props, for example mycustomprop="someValue". This can be useful when integrating with third-party libraries. The custom attribute name must be lowercase and must not start with on. The value will be converted to a string. If you pass null or undefined, the custom attribute will be removed.

These events fire only for the <form> elements:

• onReset: An Event handler function. Fires when a form gets reset.
• onResetCapture: A version of onReset that fires in the capture phase.
• onSubmit: An Event handler function. Fires when a form gets submitted.
• onSubmitCapture: A version of onSubmit that fires in the capture phase.

These events fire only for the <dialog> elements. Unlike browser events, they bubble in React:

• onCancel: An Event handler function. Fires when the user tries to dismiss the dialog.
• onCancelCapture: A version of onCancel that fires in the capture phase.
• onClose: An Event handler function. Fires when a dialog has been closed.
• onCloseCapture: A version of onClose that fires in the capture phase.

These events fire only for the <details> elements. Unlike browser events, they bubble in React:

• onToggle: An Event handler function. Fires when the user toggles the details.
• onToggleCapture: A version of onToggle that fires in the capture phase.

These events fire for <img>, <iframe>, <object>, <embed>, <link>, and SVG <image> elements. Unlike browser events, they bubble in React:

• onLoad: An Event handler function. Fires when the resource has loaded.
• onLoadCapture: A version of onLoad that fires in the capture phase.
• onError: An Event handler function. Fires when the resource could not be loaded.
• onErrorCapture: A version of onError that fires in the capture phase.

These events fire for resources like <audio> and <video>. Unlike browser events, they bubble in React:

• onAbort: An Event handler function. Fires when the resource has not fully loaded, but not due to an error.
• onAbortCapture: A version of onAbort that fires in the capture phase.
• onCanPlay: An Event handler function. Fires when there’s enough data to start playing, but not enough to play to the end without buffering.
• onCanPlayCapture: A version of onCanPlay that fires in the capture phase.
• onCanPlayThrough: An Event handler function. Fires when there’s enough data that it’s likely possible to start playing without buffering until the end.
• onCanPlayThroughCapture: A version of onCanPlayThrough that fires in the capture phase.
• onDurationChange: An Event handler function. Fires when the media duration has updated.
• onDurationChangeCapture: A version of onDurationChange that fires in the capture phase.
• onEmptied: An Event handler function. Fires when the media has become empty.
• onEmptiedCapture: A version of onEmptied that fires in the capture phase.
• onEncrypted: An Event handler function. Fires when the browser encounters encrypted media.
• onEncryptedCapture: A version of onEncrypted that fires in the capture phase.
• onEnded: An Event handler function. Fires when the playback stops because there’s nothing left to play.
• onEndedCapture: A version of onEnded that fires in the capture phase.
• onError: An Event handler function. Fires when the resource could not be loaded.
• onErrorCapture: A version of onError that fires in the capture phase.
• onLoadedData: An Event handler function. Fires when the current playback frame has loaded.
• onLoadedDataCapture: A version of onLoadedData that fires in the capture phase.
• onLoadedMetadata: An Event handler function. Fires when metadata has loaded.
• onLoadedMetadataCapture: A version of onLoadedMetadata that fires in the capture phase.
• onLoadStart: An Event handler function. Fires when the browser started loading the resource.
• onLoadStartCapture: A version of onLoadStart that fires in the capture phase.
• onPause: An Event handler function. Fires when the media was paused.
• onPauseCapture: A version of onPause that fires in the capture phase.
• onPlay: An Event handler function. Fires when the media is no longer paused.
• onPlayCapture: A version of onPlay that fires in the capture phase.
• onPlaying: An Event handler function. Fires when the media starts or restarts playing.
• onPlayingCapture: A version of onPlaying that fires in the capture phase.
• onProgress: An Event handler function. Fires periodically while the resource is loading.
• onProgressCapture: A version of onProgress that fires in the capture phase.
• onRateChange: An Event handler function. Fires when playback rate changes.
• onRateChangeCapture: A version of onRateChange that fires in the capture phase.
• onResize: An Event handler function. Fires when video changes size.
• onResizeCapture: A version of onResize that fires in the capture phase.
• onSeeked: An Event handler function. Fires when a seek operation completes.
• onSeekedCapture: A version of onSeeked that fires in the capture phase.
• onSeeking: An Event handler function. Fires when a seek operation starts.
• onSeekingCapture: A version of onSeeking that fires in the capture phase.
• onStalled: An Event handler function. Fires when the browser is waiting for data but it keeps not loading.
• onStalledCapture: A version of onStalled that fires in the capture phase.
• onSuspend: An Event handler function. Fires when loading the resource was suspended.
• onSuspendCapture: A version of onSuspend that fires in the capture phase.
• onTimeUpdate: An Event handler function. Fires when the current playback time updates.
• onTimeUpdateCapture: A version of onTimeUpdate that fires in the capture phase.
• onVolumeChange: An Event handler function. Fires when the volume has changed.
• onVolumeChangeCapture: A version of onVolumeChange that fires in the capture phase.
• onWaiting: An Event handler function. Fires when the playback stopped due to temporary lack of data.
• onWaitingCapture: A version of onWaiting that fires in the capture phase.

Caveats

• You cannot pass both children and dangerouslySetInnerHTML at the same time.
• Some events (like onAbort and onLoad) don’t bubble in the browser, but bubble in React.

ref callback function

Instead of a ref object (like the one returned by useRef), you may pass a function to the ref attribute.

<div ref={(node) => console.log(node)} />

See an example of using the ref callback.

When the <div> DOM node is added to the screen, React will call your ref callback with the DOM node as the argument. When that <div> DOM node is removed, React will call your ref callback with null.

React will also call your ref callback whenever you pass a different ref callback. In the above example, (node) => { ... } is a different function on every render. When your component re-renders, the previous function will be called with null as the argument, and the next function will be called with the DOM node.

Parameters

• node: A DOM node or null. React will pass you the DOM node when the ref gets attached, and null when the ref gets detached. Unless you pass the same function reference for the ref callback on every render, the callback will get temporarily detached and re-attached during every re-render of the component.

<div ref={(node) => {
  console.log(node);

  return () => {
    console.log('Clean up', node)
  }
}}>

React event object

Your event handlers will receive a React event object. It is also sometimes known as a “synthetic event”.

<button onClick={e => {
  console.log(e); // React event object
}} />

It conforms to the same standard as the underlying DOM events, but fixes some browser inconsistencies.

Some React events do not map directly to the browser’s native events. For example in onMouseLeave, e.nativeEvent will point to a mouseout event. The specific mapping is not part of the public API and may change in the future. If you need the underlying browser event for some reason, read it from e.nativeEvent.

Properties

React event objects implement some of the standard Event properties:

• bubbles: A boolean. Returns whether the event bubbles through the DOM.
• cancelable: A boolean. Returns whether the event can be canceled.
• currentTarget: A DOM node. Returns the node to which the current handler is attached in the React tree.
• defaultPrevented: A boolean. Returns whether preventDefault was called.
• eventPhase: A number. Returns which phase the event is currently in.
• isTrusted: A boolean. Returns whether the event was initiated by user.
• target: A DOM node. Returns the node on which the event has occurred (which could be a distant child).
• timeStamp: A number. Returns the time when the event occurred.

Additionally, React event objects provide these properties:

• nativeEvent: A DOM Event. The original browser event object.

Methods

React event objects implement some of the standard Event methods:

• preventDefault(): Prevents the default browser action for the event.
• stopPropagation(): Stops the event propagation through the React tree.

Additionally, React event objects provide these methods:

• isDefaultPrevented(): Returns a boolean value indicating whether preventDefault was called.
• isPropagationStopped(): Returns a boolean value indicating whether stopPropagation was called.
• persist(): Not used with React DOM. With React Native, call this to read event’s properties after the event.
• isPersistent(): Not used with React DOM. With React Native, returns whether persist has been called.

Caveats

• The values of currentTarget, eventPhase, target, and type reflect the values your React code expects. Under the hood, React attaches event handlers at the root, but this is not reflected in React event objects. For example, e.currentTarget may not be the same as the underlying e.nativeEvent.currentTarget. For polyfilled events, e.type (React event type) may differ from e.nativeEvent.type (underlying type).

AnimationEvent handler function

An event handler type for the CSS animation events.

<div
  onAnimationStart={e => console.log('onAnimationStart')}
  onAnimationIteration={e => console.log('onAnimationIteration')}
  onAnimationEnd={e => console.log('onAnimationEnd')}
/>

Parameters

• e: A React event object with these extra AnimationEvent properties:
  • animationName
  • elapsedTime
  • pseudoElement

ClipboardEvent handler function

An event handler type for the Clipboard API events.

<input
  onCopy={e => console.log('onCopy')}
  onCut={e => console.log('onCut')}
  onPaste={e => console.log('onPaste')}
/>

Parameters

• e: A React event object with these extra ClipboardEvent properties:

  • clipboardData

CompositionEvent handler function

An event handler type for the input method editor (IME) events.

<input
  onCompositionStart={e => console.log('onCompositionStart')}
  onCompositionUpdate={e => console.log('onCompositionUpdate')}
  onCompositionEnd={e => console.log('onCompositionEnd')}
/>

Parameters

• e: A React event object with these extra CompositionEvent properties:
  • data

DragEvent handler function

An event handler type for the HTML Drag and Drop API events.

<>
  <div
    draggable={true}
    onDragStart={e => console.log('onDragStart')}
    onDragEnd={e => console.log('onDragEnd')}
  >
    Drag source
  </div>

  <div
    onDragEnter={e => console.log('onDragEnter')}
    onDragLeave={e => console.log('onDragLeave')}
    onDragOver={e => { e.preventDefault(); console.log('onDragOver'); }}
    onDrop={e => console.log('onDrop')}
  >
    Drop target
  </div>
</>

Parameters

• e: A React event object with these extra DragEvent properties:

  • dataTransfer

  It also includes the inherited MouseEvent properties:

  • altKey
  • button
  • buttons
  • ctrlKey
  • clientX
  • clientY
  • getModifierState(key)
  • metaKey
  • movementX
  • movementY
  • pageX
  • pageY
  • relatedTarget
  • screenX
  • screenY
  • shiftKey

  It also includes the inherited UIEvent properties:

  • detail
  • view

FocusEvent handler function

An event handler type for the focus events.

<input
  onFocus={e => console.log('onFocus')}
  onBlur={e => console.log('onBlur')}
/>

See an example.

Parameters

• e: A React event object with these extra FocusEvent properties:

  • relatedTarget

  It also includes the inherited UIEvent properties:

  • detail
  • view

Event handler function

An event handler type for generic events.

Parameters

• e: A React event object with no additional properties.

InputEvent handler function

An event handler type for the onBeforeInput event.

<input onBeforeInput={e => console.log('onBeforeInput')} />

Parameters

• e: A React event object with these extra InputEvent properties:
  • data

KeyboardEvent handler function

An event handler type for keyboard events.

<input
  onKeyDown={e => console.log('onKeyDown')}
  onKeyUp={e => console.log('onKeyUp')}
/>

See an example.

Parameters

• e: A React event object with these extra KeyboardEvent properties:

  • altKey
  • charCode
  • code
  • ctrlKey
  • getModifierState(key)
  • key
  • keyCode
  • locale
  • metaKey
  • location
  • repeat
  • shiftKey
  • which

  It also includes the inherited UIEvent properties:

  • detail
  • view

MouseEvent handler function

An event handler type for mouse events.

<div
  onClick={e => console.log('onClick')}
  onMouseEnter={e => console.log('onMouseEnter')}
  onMouseOver={e => console.log('onMouseOver')}
  onMouseDown={e => console.log('onMouseDown')}
  onMouseUp={e => console.log('onMouseUp')}
  onMouseLeave={e => console.log('onMouseLeave')}
/>

See an example.

Parameters

• e: A React event object with these extra MouseEvent properties:

  • altKey
  • button
  • buttons
  • ctrlKey
  • clientX
  • clientY
  • getModifierState(key)
  • metaKey
  • movementX
  • movementY
  • pageX
  • pageY
  • relatedTarget
  • screenX
  • screenY
  • shiftKey

  It also includes the inherited UIEvent properties:

  • detail
  • view

PointerEvent handler function

An event handler type for pointer events.

<div
  onPointerEnter={e => console.log('onPointerEnter')}
  onPointerMove={e => console.log('onPointerMove')}
  onPointerDown={e => console.log('onPointerDown')}
  onPointerUp={e => console.log('onPointerUp')}
  onPointerLeave={e => console.log('onPointerLeave')}
/>

See an example.

Parameters

• e: A React event object with these extra PointerEvent properties:

  • height
  • isPrimary
  • pointerId
  • pointerType
  • pressure
  • tangentialPressure
  • tiltX
  • tiltY
  • twist
  • width

  It also includes the inherited MouseEvent properties:

  • altKey
  • button
  • buttons
  • ctrlKey
  • clientX
  • clientY
  • getModifierState(key)
  • metaKey
  • movementX
  • movementY
  • pageX
  • pageY
  • relatedTarget
  • screenX
  • screenY
  • shiftKey

  It also includes the inherited UIEvent properties:

  • detail
  • view

TouchEvent handler function

An event handler type for touch events.

<div
  onTouchStart={e => console.log('onTouchStart')}
  onTouchMove={e => console.log('onTouchMove')}
  onTouchEnd={e => console.log('onTouchEnd')}
  onTouchCancel={e => console.log('onTouchCancel')}
/>

Parameters

• e: A React event object with these extra TouchEvent properties:

  • altKey
  • ctrlKey
  • changedTouches
  • getModifierState(key)
  • metaKey
  • shiftKey
  • touches
  • targetTouches

  It also includes the inherited UIEvent properties:

  • detail
  • view

TransitionEvent handler function

An event handler type for the CSS transition events.

<div
  onTransitionEnd={e => console.log('onTransitionEnd')}
/>

Parameters

• e: A React event object with these extra TransitionEvent properties:
  • elapsedTime
  • propertyName
  • pseudoElement

UIEvent handler function

An event handler type for generic UI events.

<div
  onScroll={e => console.log('onScroll')}
/>

Parameters

• e: A React event object with these extra UIEvent properties:
  • detail
  • view

WheelEvent handler function

An event handler type for the onWheel event.

<div
  onWheel={e => console.log('onWheel')}
/>

Parameters

• e: A React event object with these extra WheelEvent properties:

  • deltaMode
  • deltaX
  • deltaY
  • deltaZ

  It also includes the inherited MouseEvent properties:

  • altKey
  • button
  • buttons
  • ctrlKey
  • clientX
  • clientY
  • getModifierState(key)
  • metaKey
  • movementX
  • movementY
  • pageX
  • pageY
  • relatedTarget
  • screenX
  • screenY
  • shiftKey

  It also includes the inherited UIEvent properties:

  • detail
  • view

Usage

Applying CSS styles

In React, you specify a CSS class with className. It works like the class attribute in HTML:

<img className="avatar" />

Then you write the CSS rules for it in a separate CSS file:

/* In your CSS */
.avatar {
  border-radius: 50%;
}

React does not prescribe how you add CSS files. In the simplest case, you’ll add a <link> tag to your HTML. If you use a build tool or a framework, consult its documentation to learn how to add a CSS file to your project.

Sometimes, the style values depend on data. Use the style attribute to pass some styles dynamically:

<img
  className="avatar"
  style={{
    width: user.imageSize,
    height: user.imageSize
  }}
/>

In the above example, style={{}} is not a special syntax, but a regular {} object inside the style={ } JSX curly braces. We recommend only using the style attribute when your styles depend on JavaScript variables.

import cn from 'classnames';

function Row({ isSelected }) {
  return (
    <div className={cn('row', isSelected && 'selected')}>
      ...
    </div>
  );
}

import cn from 'classnames';

function Row({ isSelected, size }) {
  return (
    <div className={cn('row', {
      selected: isSelected,
      large: size === 'large',
      small: size === 'small',
    })}>
      ...
    </div>
  );
}

Manipulating a DOM node with a ref

Sometimes, you’ll need to get the browser DOM node associated with a tag in JSX. For example, if you want to focus an <input> when a button is clicked, you need to call focus() on the browser <input> DOM node.

To obtain the browser DOM node for a tag, declare a ref and pass it as the ref attribute to that tag:

import { useRef } from 'react';

export default function Form() {
  const inputRef = useRef(null);
  // ...
  return (
    <input ref={inputRef} />
    // ...

React will put the DOM node into inputRef.current after it’s been rendered to the screen.

Read more about manipulating DOM with refs and check out more examples.

For more advanced use cases, the ref attribute also accepts a callback function.

Dangerously setting the inner HTML

You can pass a raw HTML string to an element like so:

const markup = { __html: '<p>some raw html</p>' };
return <div dangerouslySetInnerHTML={markup} />;

This is dangerous. As with the underlying DOM innerHTML property, you must exercise extreme caution! Unless the markup is coming from a completely trusted source, it is trivial to introduce an XSS vulnerability this way.

For example, if you use a Markdown library that converts Markdown to HTML, you trust that its parser doesn’t contain bugs, and the user only sees their own input, you can display the resulting HTML like this:

The {__html} object should be created as close to where the HTML is generated as possible, like the above example does in the renderMarkdownToHTML function. This ensures that all raw HTML being used in your code is explicitly marked as such, and that only variables that you expect to contain HTML are passed to dangerouslySetInnerHTML. It is not recommended to create the object inline like <div dangerouslySetInnerHTML={{__html: markup}} />.

To see why rendering arbitrary HTML is dangerous, replace the code above with this:

const post = {
  // Imagine this content is stored in the database.
  content: `<img src="" onerror='alert("you were hacked")'>`
};

export default function MarkdownPreview() {
  // 🔴 SECURITY HOLE: passing untrusted input to dangerouslySetInnerHTML
  const markup = { __html: post.content };
  return <div dangerouslySetInnerHTML={markup} />;
}

The code embedded in the HTML will run. A hacker could use this security hole to steal user information or to perform actions on their behalf. Only use dangerouslySetInnerHTML with trusted and sanitized data.

Handling mouse events

This example shows some common mouse events and when they fire.

Handling pointer events

This example shows some common pointer events and when they fire.

Handling focus events

In React, focus events bubble. You can use the currentTarget and relatedTarget to differentiate if the focusing or blurring events originated from outside of the parent element. The example shows how to detect focusing a child, focusing the parent element, and how to detect focus entering or leaving the whole subtree.

Handling keyboard events

This example shows some common keyboard events and when they fire.