nsIJSXMLHttpRequest in Firefox 2.0

 Meant to be a script-only mechanism for setting an error event listener.
 The attribute is expected to be JavaScript function object. When
 the error event occurs, the function is invoked.
 This attribute should not be used from native code!!

 After the initial response, all event listeners will be cleared.
 Call open() before setting new event listeners.

 Mozilla only.

 Meant to be a script-only mechanism for setting a load event listener.
 The attribute is expected to be JavaScript function object. When
 the load event occurs, the function is invoked.
 This attribute should not be used from native code!!

 After the initial response, all event listeners will be cleared.
 Call open() before setting new event listeners.

 Mozilla only.

 Meant to be a script-only mechanism for setting a progress event listener.
 The attribute is expected to be JavaScript function object. When
 the error event occurs, the function is invoked.
 This attribute should not be used from native code!!
 This event listener may be called multiple times during the open request.

 After the initial response, all event listeners will be cleared.
 Call open() before setting new event listeners.

 Mozilla only.

 Meant to be a script-only mechanism for setting a callback function.
 The attribute is expected to be JavaScript function object. When the
 readyState changes, the callback function will be called.
 This attribute should not be used from native code!!

 After the initial response, all event listeners will be cleared.
 Call open() before setting new event listeners.