Simple XPConnect Scriptable Sample Plug-in 
 
This sample plug-in demonstrates how to write a XPConnect-enabled plug-in. You
should see in the plug-in rectangle below with the text "Hello World". The text
box and buttons demostrate calling the scriptable xpcom interfaces of the plugin
from JavaScript.
Problems?
- Can't load pluign:
Copy the compiled plugin to your plugins directory 
- JavaScript error in the JavaScript console talking about how 
XPConnect can't build a wrapper: 
Copy the type library (nsISimplePluginInstance.xpt) to the mozilla components
directory.
- Plugin loads, but when I push the 'Set Text' button the plugin text 
is not updated: 
Are you not running Windows? Only the Windows version updates text the plugin 
draws. But the calls from JS to the plugin should work on all platforms.
[We welcome fixes to the samples if you'd like to submit them]