Question

Every time I log on to my webmail I see a bar like on image below. I don’t want to add this as an application and it is pretty annoying to close this every time. How can I disable it permanently?

The bar says:

Add o2 Poczta (poczta.o2.pl) as an application for mailto links? [Add
Application] x

Image:
https://i.stack.imgur.com/itY4O.jpg

I tried to use Firebug to see what causes this bar to appear but with no luck. Anyone help?
I think there might me something on server side that makes Firefox behave in this way.
How did they do that?

url to webmail is http://poczta.o2.pl

Answer 1

This is done by registering a protocol handler. From that page:

navigator.registerProtocolHandler("mailto",
                              "https://www.example.com/?uri=%s",
                              "Example Mail");

The site would just have to run a similar snippet at an appropriate moment(login, in your case).