nsIDOMStorage 编辑

dom/interfaces/storage/nsIDOMStorage.idlScriptable This interface represents the storage space used for session storage in the DOM. Items stored in session storage may be accessed by any interested party in the same browsing context. 1.0 66 Introduced Gecko 1.8.1 Inherits from: nsISupports Last changed in Gecko 1.9.2 (Firefox 3.6 / Thunderbird 3.1 / Fennec 1.0)

A DOM window's session storage object can be retrieved from the window's sessionStorage attribute.

A storage object stores an arbitrary set of key-value pairs, which may be retrieved, modified and removed as needed. A key may only exist once within a storage object, and only one value may be associated with a particular key. Keys are stored in a particular order with the condition that this order not change by merely changing the value associated with a key, but the order may change when a key is added or removed.

Method overview

void clear();

DOMString getItem(in DOMString key);

DOMString key(in unsigned long index);

void removeItem(in DOMString key);

void setItem(in DOMString key, in DOMString data);

Attributes

Attribute	Type	Description
length	unsigned long	The number of keys stored in the session store. Read only.

Methods

clear()

Clear the content of this storage bound to a domain or an origin.

void clear();

Parameters

None.

getItem()

Returns from session storage the data corresponding to the specified key.

DOMString getItem(
  in DOMString key
);

Parameters

key

The key for which data should be returned.

Return value

An nsIDOMStorageItem object describing the data corresponding to the specified key, or null if no data exists for the given key.

key()

Returns the key for the item stored at the specified index in the data store.

DOMString key(
  in unsigned long index
);

Parameters

index

The index for which the corresponding key should be returned.

Return value

A string containing the requested key.

Exceptions thrown

INDEX_SIZE_ERR

There is no key at the specified index.

removeItem()

Given a key, removes the corresponding entry from the session store.

void removeItem(
  in DOMString key
);

Parameters

key

The key for which data should be removed from storage.

setItem()

Sets the value corresponding to a given key. If the key does not already exist, a new key is added, associated with the specified value. If the key already exists, the existing value is replaced with the specified value.

void setItem(
  in DOMString key,
  in DOMString data
);

Parameters

key

The key for which data should be set.

data

The data to associate with the specified key.

See also

• DOM Storage
• Structured client-side storage (HTML 5 specification)
• nsIDOMStorageItem