This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

The Node.setUserData() method allows a user to attach (or remove) data to an element, without needing to modify the DOM. Note that such data will not be preserved when imported via Node.importNode, as with Node.cloneNode() and Node.renameNode() operations (though Node.adoptNode does preserve the information), and equality tests in Node.isEqualNode() do not consider user data in making the assessment.

This method offers the convenience of associating data with specific nodes without needing to alter the structure of a document and in a standard fashion, but it also means that extra steps may need to be taken if one wishes to serialize the information or include the information upon clone, import, or rename operations.

The Node.getUserData and Node.setUserData methods are no longer available from Web content. HTMLElement.dataset or WeakMap can be used instead.


var prevUserData = someNode.setUserData(userKey, userData, handler);


  • userKey is used as the key by which one may subsequently obtain the stored data. More than one key can be set for a given node.
  • handler is a callback which will be called any time the node is being cloned, imported, renamed, as well as if deleted or adopted; a function can be used or an object implementing the handle method (part of the UserDataHandler interface). The handler will be passed five arguments: an operation type integer (e.g., 1 to indicate a clone operation), the user key, the data on the node, the source node (null if being deleted), the destination node (the newly created node or null if none).If no handler is desired, one must specify null.
  • userData is the object to associate to userKey on someNode. If null, any previously registered object and UserDataHandler associated to userKey on this node will be removed.


var d = document.implementation.createDocument('', 'test', null);
d.documentElement.setUserData('key', 15, {handle:function (o, k, d, s, ds) {console.log(o+'::'+k+'::'+d+'::'+s+'::'+ds)}}); // 2::key::15::[object Element]::[object Element]
console.log(d.documentElement.getUserData('key')); // 15
var e = document.importNode(d.documentElement, true); // causes handler to be called
console.log(e.getUserData('key')); // null since user data is not copied


Specification Status Comment
Document Object Model (DOM) Level 3 Core Specification
The definition of 'Node.setUserData()' in that specification.
Obsolete Initial definition

Browser compatibility

BCD tables only load in the browser

See also