I've just filed a bug with ajax context which, in a nutshell, is that a clone of the context object is passed into the callbacks rather than the object itself. This pretty much makes the object read-only. 

Current code:

 

  
 ajax: function( origSettings ) {
  
 var s = jQuery.extend(true, {}, jQuery.ajaxSettings, origSettings);
  
 var jsonp, status, data,
  
 callbackContext = s.context || s,

 

Looking at this, it has just occurred to me that jQuery.ajax is unnecessarily deep cloning the context object, which is a big literal object "namespace".

Isn't this a potential scaling problem; since the need for context correlates with the context object's complexity? (bigger namespace => more need for context => more to extend => slower ajax calls).

Perhaps a better way to handle this is to remove the context property reference of origSettings while extend does it's work?