iCloud Mail 'mailto' link handler for Desktop browsers on Windows

Hi there,

I'm using a Windows PC with a Firefox browser and I wish that when I click links on the web that start with:

mailto:

that it will open a new tab with a new message on iCloud Mail web-based service with the address that comes after the the "mailto:" part inserted in the "To:" in the new email tab. As far as I know, many web-based Email services aid users to set this setting in their browser so these links will be redirected to their service, but it seems that iCloud Mail doesn't do much to help in that regard.

So far I managed to add a new 'mailto' handler in the settings, but the address I found on the internet that is joined by that handler doesn't work unfortunately. (The invalid handler link was: https://www.icloud.com/message/current/en-us/#compose?to=%s)

I most importantly need the address that will make the handler work with the web-based iCloud Mail.

Thank you for reading and for anyone who tries to help :)