Adobe® AIR® uses
WebKit
(www.webkit.org
),
also used by the Safari web browser, to parse, layout, and render
HTML and JavaScript content. Using the AIR APIs in HTML content
is optional. You can program in the content of an HTMLLoader object
or HTML window entirely with HTML and JavaScript. Most existing
HTML pages and applications should run with few changes (assuming
they use HTML, CSS, DOM, and JavaScript features compatible with
WebKit).
Important:
New versions of the Adobe AIR runtime may include
updated versions of WebKit. A WebKit update in a new version of
AIR
may
result in unexpected changes in a deployed AIR application.
These changes may affect the behavior or appearance of HTML content
in an application. For example, improvements or corrections in WebKit
rendering may change the layout of elements in an application’s
user interface. For this reason, it is highly recommended that you
provide an update mechanism in your application. Should you need
to update your application due to a change in the WebKit version
included in AIR, the AIR update mechanism can prompt the user to
install the new version of your application.
The following table lists the version of the Safari web browser
that uses the version of WebKit equivalent to that used in AIR:
|
AIR version
|
Safari version
|
|
1.0
|
2.04
|
|
1.1
|
3.04
|
|
1.5
|
4.0 Beta
|
|
2.0
|
4.03
|
|
2.5
|
4.03
|
|
2.6
|
4.03
|
|
2.7
|
4.03
|
|
3
|
5.0.3
|
You can always determine the installed version of WebKit by examining
the default user agent string returned by a HTMLLoader object:
var htmlLoader:HTMLLoader = new HTMLLoader();
trace( htmlLoader.userAgent );
Keep in mind that the version of WebKit used in AIR is not identical
to the open source version. Some features are not supported in AIR
and the AIR version can include security and bug fixes not yet available
in the corresponding WebKit version. See
WebKit features not supported in AIR
.
Because
AIR applications run directly on the desktop, with full access to
the file system, the security model for HTML content is more stringent
than the security model of a typical web browser. In AIR, only content
loaded from the application installation directory is placed in
the
application sandbox
. The application sandbox has the
highest level of privilege and allows access to the AIR APIs. AIR
places other content into isolated sandboxes based on where that
content came from. Files loaded from the file system go into a local
sandbox. Files loaded from the network using the http: or https:
protocols go into a sandbox based on the domain of the remote server.
Content in these non-application sandboxes is prohibited from accessing
any AIR API and runs much as it would in a typical web browser.
HTML content in AIR does not display SWF or PDF content if alpha,
scaling, or transparency settings are applied. For more information,
see
Considerations when loading SWF or PDF content in an HTML page
and
Window transparency
.
