Not sure what you are attempting to do.

If you have a webpage open in the active tab the locationbar gives the web pages address. Keyboard shortcut Ctrl+L will give that focus. Ctrl+C will copy it and Crl+V will paste it.

I will try to explain in more detail. When creating a spread sheet in EXCEL you create a line of data in various columns. You know there is a particular web address that has additional information to the line of data entered. In EXPLORER it is possible to HYPERLINK a cell in the line of data that will take you directly to the web site when it is clicked on. This has been a standard feature in EXPLORER for a very long time.

When you follow a hyperlink in Excel, usually it should open in your default browser. You shouldn't have to do anything special in Excel to create the link when Firefox is your default browser compared with IE. However, the Insert Hyperlink dialog might work differently. I think it might be able to automatically pre-populate a URL from IE, while in Firefox, you need to copy the URL from Firefox's address bar and paste it into the Insert Link dialog.