XE.com Currency Converter
XE.com Currency Converter is a handy and reliable Firefox extension designed to implement the possibility to convert between various currencies using the XE online service.
The add-on is available in XPI format and you can install it by dragging and dropping onto an open Firefox window. You will then notice its presence through a button that should become visible in the add-on toolbar.
If you can’t spot it, you can navigate to the Customization toolbar inside Firefox and drag the corresponding icon to wherever you like inside the browser. Once you press the button, the extension will ask you to specify the amount that you wish to convert in the original currency, after which you are required to select the output currency.
In order for the conversion to be successful, you must enter the currencies in the format specific to ISO codes, using three characters. If you don’t know the symbols of the currencies, you can use a search engine to retrieve this type of information.
Provided that you’ve specified them correctly, the extension connects to the XE.com service and performs the conversion in the background, following which it displays the results in a little dialog box. Another conversion can be started by clicking on the add-on’s icon again.