Windows 7: Adding Hotmail as Default Email in Firefox 8.0.1

I was using Firefox 8.0.1 in Windows 7.  (Apparently these instructions would also work for Firefox 3.0.)  I was looking at a webpage containing an email address.  I clicked on the email link and got a dialog saying this:

Launch Application

This link needs to be opened with an application.
Send to:
Thunderbird
Yahoo! Mail
Gmail

Choose an Application

Hotmail was not on the list.  But I wanted to use Hotmail.  To find a solution, I did a search and wound up with some advice on the process.  I decided to save a writeup of the advice here because it took me a while to find it.

The advice was to type "about:config" in the Firefox address bar, hit Enter, type "gecko" into the Filter box, and double-click on the first item on the list.  This was the item called "gecko.handlerService.allowRegisterFromDifferentHost."  Double-clicking on it put it into boldface and changed its value from false to true.  Then I closed the about:config tab.  I went back to the address bar and typed this command, all on a single line:

Javascript:window.navigator.registerProtocolHandler("mailto","http://hotmail.msn.com/secure/start?action=compose&to=%s","Hotmail")

and then I hit Enter.  This gave me a bar at the top with the question, "Add Hotmail (hotmail.msn.com) as an application for mailto links?"  I clicked on "Add Application."  That gave me a blank screen.  I went to Tools > Options > Applications.  There were a bunch of items listed there.  I went down the Content Type column until I found "mailto."  I selected it.  This gave me a drop-down menu on the right side.  I selected the "Use Hotmail" option and clicked OK.

I went back to the webpage where I saw that email link.  I clicked on that link.  This opened up the Hotmail sign-in webpage.  I signed in.  Hotmail immediately started an email addressed to that email address.  I composed and sent an email.  It seemed to go OK.  Problem solved.