DirectFileOpener is a Firefox Addon that opens files in the associated application without any user nags or prompts. The primary use of this addon is with the FormEntry Module, where we open .infopathxml files in Microsoft InfoPath without asking the user to save the file to some location and then open the file in InfoPath.
The addon is known to improve productivity of data assistants and saves valuable clicks
The Addon works in Windows with Firefox v1.5 - v3.0.5 (latest stable) and requires InfoPath to be installed.
Click here to install the addon. (You have allow any security prompts)
Browse the source code.