Since I recently start using Firefox 3 and even more recently using Google Apps For Your Domain (GAFYD) as my primary email client, there has been one little annoyance I wanted to fix.
When coming across a mailto: link (a link you click on in a website to start a new email message) it would not bring up my proper email. There is a Gmail option in Firefox 3, but that is only for the public hosted @gmail.com addresses. I need something for GAFYD email, so I began searching.
I came across this blog article which solved my problem perfectly. I decided to reformat the instructions slightly and post below.
- In the Firefox address bar type
about:config
and press enter.
- Click the “I’ll be careful, I promise!” button.
- In the “Filter: ” field type
gecko.handlerService.allowRegisterFromDifferentHost
and press enter.
- Double click the found result to change the value from “false” to “true”.
- In the address bar type
javascript:window.navigator.registerProtocolHandler("mailto","https://mail.google.com/a/example.com/mail/?extsrc=mailto&url=%s","Google Apps") - Replace example.com with your Google Apps domain and hit enter.
- A banner should appear below your address bar and tab bar, ask you if you want to Add Google Apps to as an application for your mailto links, Click “Add Application” on the right.
- Double click the allowRegisterFromDifferentHost to change the value from “true” to “false” (restoring the default value and reversing the change made in step 4).
- In Firefox, select Tools menu, then Options…
- Click on Applications at top of Options window.
- Ensure mailto says “Use Google Apps”. If not click on the line and use arrow on right to select “Use Google Apps”

#1 by Ian on June 18, 2009 - 7:04 pm
This is great. I have one correction to suggest. There should not be a semicolon between the mailto and url tags in your javascript. As you wrote it, the to, subject, and body cannot be filled in automatically.
#2 by Wes on June 18, 2009 - 7:52 pm
Ian, thanks for the comment. This is actually a bug with the syntax highlighter plugin I am using. I am looking into changing to different one that will hopefully correct this.
#3 by t.a. mccann on December 28, 2009 - 12:36 pm
does this work the same on a Mac. I cannot get the “popup” to happen after step 5. Ideas?
#4 by Wes on December 28, 2009 - 1:03 pm
I just tested it on a Mac, but there is a problem with the text on step 5, it should read:
javascript:window.navigator.registerProtocolHandler(“mailto”,”https://mail.google.com/a/example.com/mail/?extsrc=mailto&url=%s”,”Google Apps”)
Also on Step 9 you will use Firefox menu then Preferences on the Mac. Hope that helps!