ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Security
Overview on configuring your HTML-based application
Adobe AIR 1.0 and later
Frames and iframes provide a convenient structure for organizing HTML content in AIR. Frames provide a means
both for maintaining data persistence and for working securely with remote content.
Because HTML in AIR retains its normal, page-based organization, the HTML environment completely refreshes if
the top frame of your HTML content “navigates” to a different page. You can use frames and iframes to maintain data
persistence in AIR, much the same as you would for a web application running in a browser. Define your main
application objects in the top frame and they persist as long as you don’t allow the frame to navigate to a new page. Use
child frames or iframes to load and display the transient parts of the application. (There are a variety of ways to
maintain data persistence that can be used in addition to, or instead of, frames. These include cookies, local shared
objects, local file storage, the encrypted file store, and local database storage.)
Because HTML in AIR retains its normal, blurred line between executable code and data, AIR puts content in the top
frame of the HTML environment into the application sandbox. After the page load event, AIR restricts any
operations, such as eval(), that can convert a string of text into an executable object. This restriction is enforced even
when an application does not load remote content. To allow HTML content to execute these restricted operations, you
must use frames or iframes to place the content into a non-application sandbox. (Running content in a sandboxed
child frame may be necessary when using some JavaScript application frameworks that rely on the eval() function.)
For a complete list of the restrictions on JavaScript in the application sandbox, see “Code restrictions for content in
different sandboxes” on page 1071.
Because HTML in AIR retains its ability to load remote, possibly insecure content, AIR enforces a same-origin policy
that prevents content in one domain from interacting with content in another. To allow interaction between
application content and content in another domain, you can set up a bridge to serve as the interface between a parent
and a child frame.
Setting up a parent-child sandbox relationship
Adobe AIR 1.0 and later
AIR adds the sandboxRoot and documentRoot attributes to the HTML frame and iframe elements. These attributes
let you treat application content as if it came from another domain:
Attribute Description
sandboxRoot The URL to use for determining the sandbox and domain in which to place the
frame content. The file:, http:, or https: URL schemes must be used.
documentRoot The URL from which to load the frame content. The file:, app:, or appstorage:
URL schemes must be used.
The following example maps content installed in the sandbox subdirectory of the application to run in the remote
sandbox and the www.example.com domain:
Last updated 6/6/2012
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