SyntheticEvent
Your event handlers will be passed instances of SyntheticEvent, a cross-browser wrapper around the browser's native event. It has the same interface as the browser's native event, including stopPropagation() and preventDefault(), except the events work identically across all browsers.
If you find that you need the underlying browser event for some reason, simply use the nativeEvent attribute to get it. Every SyntheticEvent object has the following attributes:
boolean bubbles boolean cancelable DOMEventTarget currentTarget boolean defaultPrevented number eventPhase boolean isTrusted DOMEvent nativeEvent void preventDefault() boolean isDefaultPrevented() void stopPropagation() boolean isPropagationStopped() DOMEventTarget target number timeStamp string type
As of v0.14, returning
falsefrom an event handler will no longer stop event propagation. Instead,e.stopPropagation()ore.preventDefault()should be triggered manually, as appropriate.
Event pooling
The SyntheticEvent is pooled. This means that the SyntheticEvent object will be reused and all properties will be nullified after the event callback has been invoked. This is for performance reasons. As such, you cannot access the event in an asynchronous way.
function onClick(event) {
console.log(event); // => nullified object.
console.log(event.type); // => "click"
var eventType = event.type; // => "click"
setTimeout(function() {
console.log(event.type); // => null
console.log(eventType); // => "click"
}, 0);
this.setState({clickEvent: event}); // Won't work. this.state.clickEvent will only contain null values.
this.setState({eventType: event.type}); // You can still export event properties.
}
If you want to access the event properties in an asynchronous way, you should call
event.persist()on the event, which will remove the synthetic event from the pool and allow references to the event to be retained by user code.
Supported Events
React normalizes events so that they have consistent properties across different browsers.
The event handlers below are triggered by an event in the bubbling phase. To register an event handler for the capture phase, append Capture to the event name; for example, instead of using onClick, you would use onClickCapture to handle the click event in the capture phase.
Clipboard Events
Event names:
onCopy onCut onPaste
Properties:
DOMDataTransfer clipboardData
Composition Events
Event names:
onCompositionEnd onCompositionStart onCompositionUpdate
Properties:
string data
Keyboard Events
Event names:
onKeyDown onKeyPress onKeyUp
Properties:
boolean altKey number charCode boolean ctrlKey boolean getModifierState(key) string key number keyCode string locale number location boolean metaKey boolean repeat boolean shiftKey number which
Focus Events
Event names:
onFocus onBlur
Properties:
DOMEventTarget relatedTarget
These focus events work on all elements in the React DOM, not just form elements.
Form Events
Event names:
onChange onInput onSubmit
For more information about the onChange event, see Forms.
Mouse Events
Event names:
onClick onContextMenu onDoubleClick onDrag onDragEnd onDragEnter onDragExit onDragLeave onDragOver onDragStart onDrop onMouseDown onMouseEnter onMouseLeave onMouseMove onMouseOut onMouseOver onMouseUp
The onMouseEnter and onMouseLeave events propagate from the element being left to the one being entered instead of ordinary bubbling and do not have a capture phase.
Properties:
boolean altKey number button number buttons number clientX number clientY boolean ctrlKey boolean getModifierState(key) boolean metaKey number pageX number pageY DOMEventTarget relatedTarget number screenX number screenY boolean shiftKey
Selection Events
Event names:
onSelect
Touch Events
Event names:
onTouchCancel onTouchEnd onTouchMove onTouchStart
Properties:
boolean altKey DOMTouchList changedTouches boolean ctrlKey boolean getModifierState(key) boolean metaKey boolean shiftKey DOMTouchList targetTouches DOMTouchList touches
UI Events
Event names:
onScroll
Properties:
number detail DOMAbstractView view
Wheel Events
Event names:
onWheel
Properties:
number deltaMode number deltaX number deltaY number deltaZ
Media Events
Event names:
onAbort onCanPlay onCanPlayThrough onDurationChange onEmptied onEncrypted onEnded onError onLoadedData onLoadedMetadata onLoadStart onPause onPlay onPlaying onProgress onRateChange onSeeked onSeeking onStalled onSuspend onTimeUpdate onVolumeChange onWaiting
Image Events
Event names:
onLoad onError
Animation Events
Event names:
onAnimationStart onAnimationEnd onAnimationIteration
Properties:
string animationName string pseudoElement float elapsedTime
Transition Events
Event names:
onTransitionEnd
Properties:
string propertyName string pseudoElement float elapsedTime
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