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.


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

attributeFilter Optional
An array of specific attribute names to be monitored. If this property isn't included, changes to all attributes cause mutation notifications. No default value.
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. No default value.
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 false.
characterData Optional
Set to true to monitor the specified target node or subtree for changes to the character data contained within the node or nodes. No default value.
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. No default value.
childList Optional
Set to true to monitor the target node (and, if subtree is true, its descendants) for the addition or removal of new child nodes. The default is false.
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.


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