[Editor's note: This post updated 4 October]

I love Firefox.

But I don’t like having to run GTalk in the background to have mailto: links open in GMail or my Hosted GMail. So, what do you do to change how mailto: links function?

It’s actually quite simple.

Open Firefox.

In the address bar type one of the following strings of code. It will vary depending on if you are using a Google Hosted account or a regular GMail account.
GMail:

javascript:window.navigator.registerProtocolHandler
("mailto","https://mail.google.com/mail/?extsrc=mailto&url=%s","Gmail")

Hosted GMail:

javascript:window.navigator.registerProtocolHandler
("mailto","https://mail.google.com/a/exampleurl.com/mail/?extsrc=mailto&url=%s","GMail")

You will be asked if you want to add GMail as a handler for mailto: links. Go ahead.

If you are not asked for any confirmation, go back to the address bar and type:

about:config

Click “I’ll be careful, I promise!”

In the filter bar type:

network.protocol-handler.external.mailto

Double-click on the entry listed under “Preference Name,” this will change the entry to “true” and appear bold.

Then verify the setup worked by going to Tools > Options.

Click “Applications” and in the “Search” box type

mailto

Make sure the drop-down on the right says “Use GMail.”

This has been one of my favorite tweaks for Firefox. And it’s made sharing things much easier, because I don’t have to “Copy link address” to send e-mails to friends.