MutationObserverInit

The MutationObserverInit dictionary describes the configuration of a mutation observer. As such, it's primarily used as the type of the options parameter on the MutationObserver.observe() method.

Properties

At a minimum, one of childList, attributes, and/or characterData must be true when you call observe(). Otherwise, a TypeError exception will be thrown.

subtree Optional
Set to true to extend monitoring to the entire subtree of nodes rooted at target. All of the other MutationObserverInit properties are then extended to all of the nodes in the subtree instead of applying solely to the target node. The default value is false.
childList Optional
Set to true to monitor the target node (and, if subtree is true, its descendants) for the addition of new child nodes or removal of existing child nodes. The default value is false.
attributes Optional
Set to true to watch for changes to the value of attributes on the node or nodes being monitored. The default value is true if either of attributeFilter or attributeOldValue is specified, otherwise the default value is false.
attributeFilter Optional
An array of specific attribute names to be monitored. If this property isn't included, changes to all attributes cause mutation notifications.
attributeOldValue Optional
Set to true to record the previous value of any attribute that changes when monitoring the node or nodes for attribute changes; see Monitoring attribute values in MutationObserver for details on watching for attribute changes and value recording. The default value is false.
characterData Optional
Set to true to monitor the specified target node (and, if subtree is true, its descendants) for changes to the character data contained within the node or nodes. The default value is true if characterDataOldValue is specified, otherwise the default value is false.
characterDataOldValue Optional
Set to true to record the previous value of a node's text whenever the text changes on nodes being monitored. For details and an example, see Monitoring text content changes in MutationObserver. The default value is false.

Specifications

Specification Status Comment
DOM
The definition of 'MutationObserverInit' in that specification.
Living Standard

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
MutationObserverInitChrome Full support 26
Full support 26
No support 18Ā ā€” 26
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge Full support 12Firefox Full support 14IE Full support 11Opera Full support 15Safari Full support 7
Full support 7
No support 6Ā ā€” 7
Prefixed
Prefixed Implemented with the vendor prefix: webkit
WebView Android ? Chrome Android Full support 26
Full support 26
No support 18Ā ā€” 26
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Firefox Android Full support 14Opera Android Full support 14Safari iOS Full support 7
Full support 7
No support 6Ā ā€” 7
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Samsung Internet Android Full support 1.5
Full support 1.5
No support 1.0Ā ā€” 1.5
Prefixed
Prefixed Implemented with the vendor prefix: webkit
attributeFilterChrome Full support 26
Full support 26
No support 18Ā ā€” 26
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge Full support 12
Notes
Full support 12
Notes
Notes Before Edge 79, this requires attributes: true when using attributeFilter. If attributes: true is not present, then Edge throws a syntax error.
Firefox Full support 14IE Full support 11
Notes
Full support 11
Notes
Notes Internet Explorer requires attributes: true when using attributeFilter. If attributes: true is not present, then Internet Explorer throws a syntax error.
Opera Full support 15Safari Full support 7
Full support 7
No support 6Ā ā€” 7
Prefixed
Prefixed Implemented with the vendor prefix: webkit
WebView Android ? Chrome Android Full support 26
Full support 26
No support 18Ā ā€” 26
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Firefox Android Full support 14Opera Android Full support 14Safari iOS Full support 7
Full support 7
No support 6Ā ā€” 7
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Samsung Internet Android Full support 1.5
Full support 1.5
No support 1.0Ā ā€” 1.5
Prefixed
Prefixed Implemented with the vendor prefix: webkit
attributeOldValueChrome Full support 26
Full support 26
No support 18Ā ā€” 26
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge Full support 12Firefox Full support 14
Notes
Full support 14
Notes
Notes Starting in Firefox 36, attributeOldValue has no default value; previously, its default value was false.
IE Full support 11Opera Full support 15Safari Full support 7
Full support 7
No support 6Ā ā€” 7
Prefixed
Prefixed Implemented with the vendor prefix: webkit
WebView Android ? Chrome Android Full support 26
Full support 26
No support 18Ā ā€” 26
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Firefox Android Full support 14
Notes
Full support 14
Notes
Notes Starting in Firefox 36, attributeOldValue has no default value; previously, its default value was false.
Opera Android Full support 14Safari iOS Full support 7
Full support 7
No support 6Ā ā€” 7
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Samsung Internet Android Full support 1.5
Full support 1.5
No support 1.0Ā ā€” 1.5
Prefixed
Prefixed Implemented with the vendor prefix: webkit
attributesChrome Full support 26
Full support 26
No support 18Ā ā€” 26
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge Full support 12Firefox Full support 14
Notes
Full support 14
Notes
Notes Starting in Firefox 36, attributes has no default value; previously, its default value was false.
IE Full support 11Opera Full support 15Safari Full support 7
Full support 7
No support 6Ā ā€” 7
Prefixed
Prefixed Implemented with the vendor prefix: webkit
WebView Android ? Chrome Android Full support 26
Full support 26
No support 18Ā ā€” 26
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Firefox Android Full support 14
Notes
Full support 14
Notes
Notes Starting in Firefox 36, attributes has no default value; previously, its default value was false.
Opera Android Full support 14Safari iOS Full support 7
Full support 7
No support 6Ā ā€” 7
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Samsung Internet Android Full support 1.5
Full support 1.5
No support 1.0Ā ā€” 1.5
Prefixed
Prefixed Implemented with the vendor prefix: webkit
characterDataChrome Full support 26
Full support 26
No support 18Ā ā€” 26
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge Full support 12Firefox Full support 14
Notes
Full support 14
Notes
Notes Starting in Firefox 36, characterData has no default value; previously, its default value was false.
IE Full support 11Opera Full support 15Safari Full support 7
Full support 7
No support 6Ā ā€” 7
Prefixed
Prefixed Implemented with the vendor prefix: webkit
WebView Android ? Chrome Android Full support 26
Full support 26
No support 18Ā ā€” 26
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Firefox Android Full support 14
Notes
Full support 14
Notes
Notes Starting in Firefox 36, characterData has no default value; previously, its default value was false.
Opera Android Full support 14Safari iOS Full support 7
Full support 7
No support 6Ā ā€” 7
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Samsung Internet Android Full support 1.5
Full support 1.5
No support 1.0Ā ā€” 1.5
Prefixed
Prefixed Implemented with the vendor prefix: webkit
characterDataOldValueChrome Full support 26
Full support 26
No support 18Ā ā€” 26
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge Full support 12Firefox Full support 14
Notes
Full support 14
Notes
Notes Starting in Firefox 36, characterDataOldValue has no default value; previously, its default value was false.
IE Full support 11Opera Full support 15Safari Full support 7
Full support 7
No support 6Ā ā€” 7
Prefixed
Prefixed Implemented with the vendor prefix: webkit
WebView Android ? Chrome Android Full support 26
Full support 26
No support 18Ā ā€” 26
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Firefox Android Full support 14
Notes
Full support 14
Notes
Notes Starting in Firefox 36, characterDataOldValue has no default value; previously, its default value was false.
Opera Android Full support 14Safari iOS Full support 7
Full support 7
No support 6Ā ā€” 7
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Samsung Internet Android Full support 1.5
Full support 1.5
No support 1.0Ā ā€” 1.5
Prefixed
Prefixed Implemented with the vendor prefix: webkit
childListChrome Full support 26
Full support 26
No support 18Ā ā€” 26
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge Full support 12Firefox Full support 14IE Full support 11Opera Full support 15Safari Full support 7
Full support 7
No support 6Ā ā€” 7
Prefixed
Prefixed Implemented with the vendor prefix: webkit
WebView Android ? Chrome Android Full support 26
Full support 26
No support 18Ā ā€” 26
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Firefox Android Full support 14Opera Android Full support 14Safari iOS Full support 7
Full support 7
No support 6Ā ā€” 7
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Samsung Internet Android Full support 1.5
Full support 1.5
No support 1.0Ā ā€” 1.5
Prefixed
Prefixed Implemented with the vendor prefix: webkit
subtreeChrome Full support 26
Full support 26
No support 18Ā ā€” 26
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge Full support 12Firefox Full support 14IE Full support 11Opera Full support 15Safari Full support 7
Full support 7
No support 6Ā ā€” 7
Prefixed
Prefixed Implemented with the vendor prefix: webkit
WebView Android ? Chrome Android Full support 26
Full support 26
No support 18Ā ā€” 26
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Firefox Android Full support 14Opera Android Full support 14Safari iOS Full support 7
Full support 7
No support 6Ā ā€” 7
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Samsung Internet Android Full support 1.5
Full support 1.5
No support 1.0Ā ā€” 1.5
Prefixed
Prefixed Implemented with the vendor prefix: webkit

Legend

Full support Ā 
Full support
Compatibility unknown Ā 
Compatibility unknown
See implementation notes.
See implementation notes.
Requires a vendor prefix or different name for use.
Requires a vendor prefix or different name for use.