Assume func is a valid function and service is an object such as: {"url": "http://host.domain.com/serviceUrl", "type": "POST"}. The contentType is honored when data is not an empty object, {}, if the data object is empty then the contentType gets mangled.

$.ajax({"url": service.url, "type": service.type, "dataType": "json", "data": data, "success": func, "contentType": "application/x-www-form-urlencoded"});

Instead of the request being made with the contentType of "application/x-www-form-urlencoded", as is supposed to be the default anyway, the request gets made with the following values for the Content-Type header:

Firefox 3.6.6 : "text/plain"

Safari 5.0: "application/xml"

So far I have only tested this on the Mac.

In my case this is preventing successful requests to a Java application since the application refuses to accept Content-Types other than application/x-www-form-urlencoded. The result is that my requests are denied. Using Charles Proxy and modifying the Content-Type header does allow my request to succeed.