Web/API/UserDataHandler

Obsolete since Gecko 26 (Firefox 26 / Thunderbird 26 / SeaMonkey 2.23 / Firefox OS 1.2)This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.

Summary

When associating user data with a key on a node, Node.setUserData() can also accept, in its third argument, a handler which will be called when the object is cloned, imported, deleted, renamed, or adopted. Per the specification, exceptions should not be thrown in a UserDataHandler. In both document.importNode() and Node.cloneNode(), although user data is not copied over, the handler will be called.

Properties

None.

Methods

handle (operation, key, data, src, dst) (no return value)

This method is a callback which will be called if a node is being cloned, imported, renamed and as well, if deleted or adopted.

operation (unsigned short) is an operation type integer (see below).
key (DOMString) is the user key.
data (DOMUserData) is the user data.
src (Node) is the source node (null if being deleted).
dst (Node) is the destination node (if any, or null).

Constants

Constant	Value	Operation
`NODE_CLONED`	1	`Node.cloneNode()`
`NODE_IMPORTED`	2	`Document.importNode()`
`NODE_DELETED` Unimplemented (see bug 550400)	3
`NODE_RENAMED` Unimplemented	4	`Node.renameNode()`
`NODE_ADOPTED`	5	`Document.adoptNode()`

(NODE_RENAMED is currently not supported since Node.renameNode() is not supported.)

Specification

DOM Level 3 Core: UserDataHandler

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`UserDataHandler` Deprecated'Non-standard'	Chrome No support No	Edge No support No	Firefox No support 4 — 22	IE No support No	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox Android No support 4 — 22	Opera Android No support No	Safari iOS No support No	Samsung Internet Android No support No
`handle` Deprecated'Non-standard'	Chrome No support No	Edge No support No	Firefox No support 4 — 22	IE No support No	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox Android No support 4 — 22	Opera Android No support No	Safari iOS No support No	Samsung Internet Android No support No

Legend

No support: No support
Non-standard. Expect poor cross-browser support.': Non-standard. Expect poor cross-browser support.
Deprecated. Not for use in new websites.': Deprecated. Not for use in new websites.