The MutationObserverInit
dictionary's optional characterDataOldValue
property is used to specify whether or not the MutationRecord.oldValue
property for DOM mutations should be set to the previous value of text nodes which changed.
If you set the MutationObserverInit.characterData
property to true
but don't set characterDataOldValue
to true
as well, the MutationRecord
will not include information describing the prior state of the text node's contents.
Character data changes are detectable on any text node, including nodes based on the Text
, ProcessingInstruction
, and Comment
interfaces.
Syntax
var options = { characterDataOldValue: true | false }
Value
A Boolean value indicating whether or not to set the MutationRecord
's oldValue
property to be a string containing the value of the character node's contents prior to the change represented by the mutation record.
By default, only changes to the text of the node specified as the target
parameter when you called observe()
are monitored. To watch for changes to the text contents of all descendants of target
, set the subtree
option to true
.
If you set characterDataOldValue
to true
, characterData
is automatically assumed to be true
, even if you don't expressly set it as such.
Example
Specifications
Specification | Status | Comment |
---|---|---|
DOM The definition of 'MutationObserverInit.characterDataOldValue' in that specification. |
Living Standard |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
characterDataOldValue | Chrome
Full support
26
| Edge Full support 12 | Firefox
Full support
14
| IE Full support 11 | Opera Full support 15 | Safari
Full support
7
| WebView Android ? | Chrome Android
Full support
26
| Firefox Android
Full support
14
| Opera Android Full support 14 | Safari iOS
Full support
7
| Samsung Internet Android
Full support
1.5
|
Legend
- Full support
- Full support
- Compatibility unknown
- 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.