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JavaScript: The Definitive Guide

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Plugin Object

Name

Plugin Object---describes an installed plug-in

Availability

Navigator 3.0

Synopsis

navigator.plugins[i]
navigator.plugins['name']

Properties

description

A read-only string that contains a human-readable description of the plug-in, specified by the plug-in itself. This property may specify a full product name, information about the vendor and version, and so on.

filename

A read-only string that specifies the name of the disk file that contains the plug-in code.

length

The number of MIME types supported by the plug-in. MimeType objects describing these types are array elements of the Plugin object.

name

A read-only string that specifies the name of the plug-in. This is generally a much shorter string than description. The value of this property may be used as an index into the navigator.plugins[] array.

Elements

The array elements of the Plugin object are MimeType objects that specify the data formats supported by the plug-in.

Description

A plug-in is a software module that can be invoked by Navigator to display specialized types of embedded data within the browser window. In Navigator 3.0, plug-ins are represented by the Plugin object. This object is somewhat unusual in that it has both regular object properties and array elements. The properties of the Plugin object provide various pieces of information about the plug-in, and the array elements of it are MimeType objects that specify the embedded data formats that the plug-in supports.

Plugin objects are obtained from the plugins[] array of the Navigator object. navigator.plugins[] may be indexed numerically when you want to loop through the complete list of installed plug-ins, looking for one that meets your needs (for example, one that supports the MIME type of the data you want to embed in your web page). This array can also be indexed by plug-in name, however. That is, if you want to check whether a specific plug-in is installed in the user's browser, you might use code like this:

document.write( navigator.plugins("Shockwave") ?
                "<EMBED SRC="movie.dir' HEIGHT=100 WIDTH=100>" :
                "You don't have the Shockwave plug-in!" );
The name used as an array index with this technique is the same name that appears as the value of the name property of the Plugin.

Don't confuse the fact that Plugin objects are stored in an array of the Navigator object with the fact that each Plugin object is itself an array of MimeType objects. Because there are two arrays involved, you may end up with code that looks like these lines:

navigator.plugins[i][j] the jth MIME type of the ith plug-in
navigator.plugins["LiveAudio"][0]   the 1st MIME type of the LiveAudio plug-in

Finally, note that while the array elements of a Plugin object specify the MIME types supported by that plug-in, you can also determine which plug-in supports a given MIME type with the enabledPlugin property of the MimeType object.

See Also

"Navigator", "MimeType", "MimeType.enabledPlugin"


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