{"json_modified": "2016-03-28T07:57:32.651306", "uuid": "99bd5dab-705f-4043-a57d-49049e1351f4", "title": "UserDataHandler", "url": "/en-US/docs/Web/API/UserDataHandler", "tags": ["Obsolete", "API", "DOM", "NeedsMarkupWork"], "translations": [], "modified": "2015-02-23T13:09:36", "label": "UserDataHandler", "localization_tags": [], "locale": "en-US", "id": 4916, "last_edit": "2015-02-22T15:18:13", "summary": "When associating user data with a key on a node, <code><a href=\"/En/DOM/Node.setUserData\" class=\"internal\" title=\"En/DOM/Node.setUserData\">Node.setUserData</a>()</code> 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 <code>UserDataHandler</code>. In both <code><a href=\"/en/DOM/document.importNode\" class=\"internal\" title=\"En/DOM/document.importNode\">document.importNode</a>()</code> and <code><a href=\"/En/DOM/Node.cloneNode\" class=\"internal\" title=\"En/DOM/Node.cloneNode\">Node.cloneNode</a>()</code>, although user data is not copied over, the handler will be called.", "sections": [{"id": "Quick_Links", "title": null}, {"id": "Summary", "title": "Summary"}, {"id": "Properties", "title": "Properties"}, {"id": "Methods", "title": "Methods"}, {"id": "Constants", "title": "Constants"}, {"id": "Specification", "title": "Specification"}, {"id": "See_also", "title": "See also"}], "slug": "Web/API/UserDataHandler", "review_tags": []}