Object of http headers for AJAX calls.
Object, default = {}
Whenever an AJAX call is made, e.g. in
.save() or
.request(), the httpHeaders object os passed along in the AJAX call.
From the JQuery.ajax docs:
An object of additional header key/value pairs to send along with requests using the XMLHttpRequest transport.
The header X-Requested-With: XMLHttpRequest is always added, but its default XMLHttpRequest value can be changed here.
Values in the headers setting can also be overwritten from within the beforeSend function.