The chromium browser offers this option when you first log in to Google Calendar:
If you have accidentally answered with
No on this question, you can press the
Wrench toolbar button and go to
Show advanced settings, find
Content settings... (just after Privacy header) and find the
Manage handlers button. Click the
X next to the ignored protocol you wish to delete. Alternatively, you can type in
protocol handlers search box in Chromium settings.See the screenshot below.
I found this post on stackexchange which explains how to achieve the same thing in Firefox,
but this doesn't work for me on firefox 12 and 15: this works for me if I disable the Never save history option (Private browsing mode):
Go to Google Calendar's site and press
Paste this after the > sign:
Press the enter key and click the
Add application button which should appear below the toolbar.
You may need to toggle the
gecko.handlerService.allowRegisterFromDifferentHost option in
true before trying this (if google redirects you to a local google domain). Remember to return it to false after calling the registerProtocolHandler function because malicious sites may exploit this. See details here.