jStorage —— store data locally with JavaScript

jStorage是一个简单的用于Prototype，MooTools，jQuery在浏览器端缓存数据（字符串，数字，对象，甚至是XML节点）的包装插件。

官方：http://jstorage.info/

方法参考：

set(key, value[, options])
$.jStorage.set(key, value, options)
Saves a value to local storage. key needs to be string otherwise an exception is thrown. value can be any JSONeable value, including objects and arrays or a XML node.
Currently XML nodes can’t be nested inside other objects: $.jStorage.set(“xml”, xml_node) is OK but $.jStorage.set(“xml”, {xml: xml_node}) is not.

Options is an optional options object. Currently only available option is options.TTL which can be used to set the TTL value to the key ($.jStorage.set(key, value, {TTL: 1000});). NB – if no TTL option value has been set, any currently used TTL value for the key will be removed.

get(key[, default])

value = $.jStorage.get(key)
value = $.jStorage.get(key, “default value”)

get retrieves the value if key exists, or default if it doesn’t. key needs to be string otherwise an exception is thrown. default can be any value.

deleteKey(key)

$.jStorage.deleteKey(key)
Removes a key from the storage. key needs to be string otherwise an exception is thrown.

setTTL(key, ttl)

$.jStorage.set(“mykey”, “keyvalue”);
$.jStorage.setTTL(“mykey”, 3000); // expires in 3 seconds
Sets a TTL (in milliseconds) for an existing key. Use 0 or negative value to clear TTL.

getTTL(key)

ttl = $.jStorage.getTTL(“mykey”); // TTL in milliseconds or 0
Gets remaining TTL (in milliseconds) for a key or 0 if not TTL has been set.

flush()

$.jStorage.flush()
Clears the cache.

index()

$.jStorage.index()
Returns all the keys currently in use as an array.
var index = $.jStorage.index();
console.log(index); // [“key1″,”key2″,”key3”]

storageSize()

$.jStorage.storageSize()
Returns the size of the stored data in bytes

currentBackend()

$.jStorage.currentBackend()
Returns the storage engine currently in use or false if none

reInit()

$.jStorage.reInit()
Reloads the data from browser storage

storageAvailable()

$.jStorage.storageAvailable()
Returns true if storage is available

subscribe(channel, callback)

$.jStorage.subscribe(“ch1″, function(channel, payload){
console.log(payload+ ” from ” + channel);
});
Subscribes to a Publish/Subscribe channel (see demo)

publish(channel, payload)

$.jStorage.publish(“ch1”, “data”);
Publishes payload to a Publish/Subscribe channel (see demo)

listenKeyChange(key, callback)

$.jStorage.listenKeyChange(“mykey”, function(key, action){
console.log(key + ” has been ” + action);
});
Listens for updates for selected key. NB! even updates made in other windows/tabs are reflected, so this feature can also be used for some kind of publish/subscribe service.

stopListening(key[, callback])

$.jStorage.stopListening(“mykey”); // cancel all listeners for “mykey” change
Stops listening for key change. If callback is set, only the used callback will be cleared, otherwise all listeners will be dropped.