javascript

Chapter 8: The Browser Object Model
name = name.toLowerCase();
for (var i=0; i < navigator.plugins.length; i++){
if (navigator.plugins[i].name.toLowerCase().indexOf(name) > -1){
return true;
}
}
}
return false;
//detect flash
alert(hasPlugin(“Flash”));
//detect quicktime
alert(hasPlugin(“QuickTime”));
The hasPlugin() example accepts a single argument: the name of a plug - in to detect. The first step is to
convert that name to lowercase for easier comparison. Next, the plugins array is iterated over and each
name property is checked via indexOf() to see if the passed - in name appears somewhere in that string.
This comparison is done in all lowercase to avoid casing errors. The argument should be as specific as
possible to avoid confusion. String such as “ Flash ” and “ QuickTime ” are unique enough that there
should be little confusion. This method works for detecting plug - ins in Firefox, Safari, Opera, and Chrome.
Each plugin object is also an array of MimeType objects that can be accessed using
bracket notation. Each MimeType object has four properties: description , which is
a description of the MIME type; enabledPlugin , which is a pointer back to the
plugin object; suffixes , which is a comma - delimited string of file extensions for
the MIME type; and type , which is the full MIME type string.
Detecting plug - ins in IE is more problematic, because it doesn ’ t support Netscape - style plug - ins.
The only way to detect plug - ins in IE is to use the proprietary ActiveXObject type and attempt to
instantiate a particular plug - in. Plug - ins are implemented in IE using COM objects, which are identified
by unique strings. So to check for a particular plug - in, you must know its COM identifier. For instance,
the identifier for Flash is ” ShockwaveFlash.ShockwaveFlash ” . With this information, you can write a
function to determine if the plug - in is installed in IE as follows:
//plugin detection for IE
function hasIEPlugin(name){
try {
new ActiveXObject(name);
return true;
} catch (ex){
return false;
}
}
//detect flash
alert(hasIEPlugin(“ShockwaveFlash.ShockwaveFlash”));
//detect quicktime
alert(hasIEPlugin(“QuickTime.QuickTime”));
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