The most effective way to determine
whether a platform is supported is to use JavaScript to query the
capabilities of the browser and change the user interface accordingly.
After you have done that, you can adjust the user
interface to re?¬‚ect the client??™s abilities. Figure 5-3 summarizes
the validation process.
Here is a JavaScript function a web developer can use to interrogate
the browser??™s support of Information Cards:
function AreCardsSupported() {
///
/// Determines if information cards are supported
/// by the browser.
/// ///
/// true-if the browser supports information cards.
Putting CardSpace to Work
Perform Client-
Side Detection
Does the
browser support
Information Cards? Yes No
Card-Enabled
Web Page
Web Page Without
Card Support
Figure 5-3 Ascertaining the client??™s capability to use Information
Cards
280 Guidance for a Relying Party
/// var IEVer = -1;
if (navigator.appName == 'Microsoft Internet
??? Explorer')
if (new RegExp("MSIE ([0-9]{1,}[\.0-9]{0,})")
.exec(navigator.userAgent) != null)
IEVer = parseFloat( RegExp.$1 );
// Look for IE 7+.
if( IEVer >= 7 ) {
var embed = document.
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