This document describes some of the changes that have been made to Gecko's XMLHttpRequest implementation since version 1.7 (i.e., the version of Gecko that shipped with Firefox 1.0). These changes only apply to XUL extensions and XUL applications. They do not apply to web applications.
Changes to XMLHttpRequest.send
If you pass a nsIInputStream instance to the send method, then it must no longer include <tt>Content-Length</tt> and <tt>Content-Type</tt> headers at the beginning of the stream. Instead, the <tt>Content-Length</tt> header will be inferred from the length of the stream, and the <tt>Content-Type</tt> header must be specified manually by calling the setRequestHeader method. These requirements are more fully described in nsIXMLHttpRequest.idl.
Changes to XMLHttpRequest.onreadystatechange
This attribute now has a type of nsIOnReadyStateChangeHandler instead of
nsIOnReadystatechangeHandler. (The "S" and the "C" in the name of the type were changed to uppercase.)