I have an ActiveX plugin that we need (if possible) to run in Firefox. Is there a plugin (or other way) for Firefox that will allow this?
I seem to have found a solution:
http://code.google.com/p/ff-activex-host/
"This Firefox plugin makes it possible to use ActiveX controls in Firefox. It is based on the Gecko NPAPI and provides full access to the hosted control (events, functions, properties)."
Not sure if this is helpful or not, but writing an NPAPI plugin for Firefox is fairly straightforward IMO - easier than writing an ActiveX control, so you might find it worthwhile to write one, especially as it should work in all the other browsers "for free".
This is a great example of a simple NPAPI plugin.
I found an other ActiveX plug-in that works. It is called neptune. See for more info http://www.meadroid.com/neptune/index.htm
You could also use firebreath, which allows you to easily create a plugin that will work on both firefox and IE; it's easy to create new methods and properties to be exposed to javascript, but you only do it in one place and it works on both browsers.
http://firebreath.googlecode.com
Yeah, I'm one of the project maintainers, so I'm biased =]
来源：https://stackoverflow.com/questions/326125/is-there-a-way-to-run-activex-components-in-firefox-through-the-use-of-a-plugin