AJAX - The Complete Reference

PART III

Chapter 10: Web Services and Beyond 535

A convenience method of getAll() is also provided that returns an array of all items in

client persistence.

To remove a value from storage, use the remove() method, passing it the key and the

persistence object:

AjaxTCR.storage.remove("way to a mans heart",persistObj);

// removed value

A similar convenience method, clear(), is provided to remove all items from storage.

The full syntax of the AjaxTCR storage mechanism is detailed in Table 10-4 and can also be

found in Appendix C.

You can try the persistence system using the AjaxTCR library in your browser with our

simple explorer program (http://ajaxref.com/ch10/persistenceexplorer.html).

Danger: Offl ine Ahead!

Just because we have saved some data into our client-side persistent storage, it doesn’t

necessarily allow us go offline. For example, let’s use our Hello World style example. If we

go offline in our browser:

and then attempt to make the call, we may raise an exception, depending on the browser.

For example, in Firefox 2 we do not seem to have problems as long as we have previously

requested the page. However, regardless of a previous request or not, in other browsers like

Internet Explorer, you will most likely throw an error when you issue the XHR request in

offline mode.