What Firefox plugin or software can open a file from the clipboard?
I've asked this on Stack Overflow: How can I start a Windows GUI program using PHP? – but it seems hard to do it only using PHP code.
Run the script (H icon will appear in tray).
The script above will open things like "c:\docs\file.html" (contained in clipboard) in FF when you press Win+H (#H). Look through autohotkey documentation to define any other hotkey. You can also extend the script's functionality to store clipboard into a file and open it with FF.