Blackberry BROWSER VERSION 4.7.0 - FUNDAMENTALS GUIDE, Основы

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• RSS 0.9, 1.0, and 2.0
• Atom™
The browser lists web feed items by date, and lists unread items in bold. When the user opens an item, the content appears in a
new page. The BlackBerry Browser does not act as an aggregator, and it does not store web feed content except as cached data.
Users can add web feeds to the bookmark list.
In BlackBerry Device Software version 4.2.2 or later, the BlackBerry Browser supports RSS enclosures, designed to provide users
with access to media files that are located at the URLs specified in the
<enclosure>
tag. In earlier versions, these links were
ignored by the browser. To access the media file, users can click the link in the web feed content.
The browser displays media files based on their type. If a URL links to an image file, the browser displays the image in the browser
window. If the URL links to an audio or video file, users can open the file, or save the file to the media card or device memory. If
the user opens the file, the browser opens the media application and begins streaming the content. Streamed content is not
saved; users cannot replay media unless they download it again.
Script processing
When the BlackBerry® Browser parses a web page, it processes JavaScript® as it is encountered. Scripts can be inline or external.
When the browser encounters a
<script>
element, it pauses web page rendering activities while it retrieves and then executes
the script. You can use the
defer
attribute to prevent the script from being processed until it is called. Unless the initial web
page content relies on the outcome of a script, you should use the defer attribute.
In BlackBerry® Device Software version 4.5 or earlier, if the BlackBerry Browser encounters any script that produces common
dynamic HTML effects, the browser executes without error but produces no visual effect. JavaScript that is not supported simply
produces an error, which, unless handled within the script, prevents the script from executing any further.
Script processing behavior varies slightly, depending on the network gateway the browser uses to access the content.
• If the content is accessed through the BlackBerry MDS Connection Service network gateway or the BlackBerry Internet
Service Browsing network gateway, the network gateway typically pre-compiles the JavaScript before sending it to the
BlackBerry device. The server can compile the script faster than the device can. When the server compiles the script, it can
reduce the time required for the browser to process the script, thereby reducing the length of time that the browser is
blocked from rendering the web page.
One obstacle to server-side preprocessing of the JavaScript occurs when an eval() function is used to execute JavaScript
code. The network gateway cannot precompile the contents of an
eval()
function. Instead, the BlackBerry Browser must
compile the code.
• If the content is accessed through a WAP network gateway, the browser compiles the code and reads any auxiliary JavaScript
support libraries that are referenced from the web page.
Fundamentals Guide Script processing
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