DOMApplicationCache Class Reference

Availability
Available in Safari 4.0 and later.
Available in iOS 2.2 and later.
Companion guide

Overview

A DOMApplicationCache object is used to store resources—such as, HTML, JavaScript, CSS, and images—locally. This allows your web application to continue running offline when there is no network connection. The cache persists after Safari exits, so it can be used by multiple browser sessions. There is one application cache per browsing context.

Tasks

Accessing Properties

Handling Events

Updating the Cache

Properties

oncached

Sent when the update process finishes for the first time—that is, the first time an application cache is saved.

attribute EventListener oncached;
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onchecking

Sent when the cache update process begins.

attribute EventListener onchecking;
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ondownloading

Sent when the update process begins downloading resources in the manifest file.

attribute EventListener ondownloading;
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onerror

Sent when an error occurs.

attribute EventListener onerror;
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onnoupdate

Sent when the update process finishes but the manifest file does not change.

attribute EventListener onnoupdate;
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onprogress

Sent when each resource in the manifest file begins to download.

attribute EventListener onprogress;
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onupdateready

Sent when there is an existing application cache, the update process finishes, and there is a new application cache ready for use.

attribute EventListener onupdateready;
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status

The current status of the application cache. One of the values described in "Constants.”

readonly attribute unsigned short status;
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Methods

swapCache

Replaces the active cache with the latest version.

void swapCache() raises(DOMException);
Availability
  • Available in Safari 4.0 and later.
  • Available in iOS 2.2 and later.

update

Manually triggers the update process.

void update() raises(DOMException);
Availability
  • Available in Safari 4.0 and later.
  • Available in iOS 2.2 and later.

Constants

Constants that indicate the status of the application cache.

Constants
UNCACHED

The object isn’t associated with an application cache. This can occur if the update process fails and there is no previous cache to revert to, or if there is no manifest file.

const unsigned short UNCACHED = 0;

Available in Safari 4.0 and later.

Available in iOS 2.2 and later.

IDLE

The cache is idle.

const unsigned short IDLE = 1;

Available in Safari 4.0 and later.

Available in iOS 2.2 and later.

CHECKING

The update has started but the resources are not downloaded yet—for example, this can happen when the manifest file is fetched.

const unsigned short CHECKING = 2;

Available in Safari 4.0 and later.

Available in iOS 2.2 and later.

DOWNLOADING

The resources are being downloaded into the cache.

const unsigned short DOWNLOADING = 3;

Available in Safari 4.0 and later.

Available in iOS 2.2 and later.

UPDATEREADY

Resources have finished downloading and the new cache is ready to be used.

const unsigned short UPDATEREADY = 4;

Available in Safari 4.0 and later.

Available in iOS 2.2 and later.