Defaulting your mailto: links to Google Apps in Firefox 3

Tim Parker

If you're using Google Apps and Firefox and would like to default email links to open in Google Apps follow the steps below.

First, make sure you're using Firefox 3. Open Firefox, and enter about:config into the address bar. This will bring up a warning message, click on the "I'll be careful, I promise!" button.

First, we need to edit the option for web pages to register themselves as protocol handlers, so enter gecko.handler in the filter bar and select the option highlighted below.

gecko.handlerService.allowRegisterFromDifferenceHost

Make sure this option is set to True (You can do so by double clicking that entry in the browser). This allows mailto: links to forward to web based email providers such as Google Apps. If you wanted to set webcal: links to a web based calendar like Google Calendar you would need this setting enabled as well.

Now that we've enabled this option we need to register Google Apps as a handler. To do this, we need to execute a single line of JavaScript. In the address bar, copy and paste the following:

javascript:window.navigator.registerProtocolHandler('mailto','https://mail.google.com/a/yourdomain.com/mail/?extsrc=mailto&url=%s','Google Apps')

Note that you will need to replace yourdomain.com with your actual domain name. Firefox will prompt you to add an application. Click "Add Application."

Finally, Navigate to Tools / Options / Applications and set Google Apps as your default for mailto.