A jQuery ajax post to a web service does nothing unless I have some sort of debugging proxy sitting between the browser and the server. For example: as soon as I turn on Fiddler, the request starts working.

This only happens in IE8 - Chrome and Firefox work as expected.

I go more into detail in a StackOverflow inquiry:

http://stackoverflow.com/questions/10452376/jquery-ajax-event-not-firing-properly-in-ie8-except-when-fiddler-is-loaded

There I have a reduced code sample, plus examples of both the outgoing and incoming JSON packets.

Older versions tested: 1.7.1

Alternate attempts: in the code sample in the SO post linked above, I build a JSON string by hand (which validates under JSLint). Since that post, I've tried using Douglas Crockford's JSON Stringifier and the data as an object to see if that changed anything. It didn't.

...
sendToServer = {
    emailAddress: myEmailAddress,
    password: myPassword,
    stayLoggedIn: myStayLoggedIn
};
...
data: JSON.stringify(sendToServer),
...