In chrome:

1.  Click the Chrome menu on the browser toolbar.

2.  Select Settings > Show advanced settings.

3.  In the "Privacy" section, click Content settings.

4.  In the dialog that appears, find the “Handlers” section:

        To allow requests, select “Allow sites to ask to become default handlers for protocols.”

5.  Click Manage handlers.

6.  Use the drop-down menu next to a listed protocol to select the web service that should be used by default.