HTML5 sessionStorage and XMLDocument

Question

I want to store an XML document in sessionStorage . When I do this it seems to save ok as an XMLDocument . When I try to access it (on a page refresh) the object comes back as [object Object] as opposed to [object XMLDocument] .

How do I get the data out of sessionStorage as an XMLDocument (or convert it to one?)

Answer 1

localStorage and sessionStorage can only hold strings. Have a look at the interface definition :

interface Storage {
  readonly attribute unsigned long length;
  [IndexGetter] DOMString key(in unsigned long index);
  [NameGetter] DOMString getItem(in DOMString key);
  [NameSetter] void setItem(in DOMString key, in DOMString data);
  [NameDeleter] void removeItem(in DOMString key);
  void clear();
};

You cannot store objects unless you serialize them. So in your case, you have to serialize it to XML .

If you received the XML document as text, just store it directly. You can use jQuery.parseXML() to parse it after retrieval.

Answer 2

You may want to serialize XMLDocument before saving it in storage:

var xml = new XMLSerializer().serializeToString(originalDom);
sessionStorage.setItem("myDocument", xml);

and then unserialize after loading data from storage:

var xml = sessionStorage.getItem("myDocument");
var restoredDom = new DOMParser().parseFromString(xml, "text/xml");