+ * (Object|String) data - Data to be sent to the server. Converted to a query
+ * string, if not already a string. Is appended to the url for GET-requests.
+ * Override processData option to prevent processing.
+ *
+ * (String) contentType - When sending data to the server, use this content-type,
+ * default is "application/x-www-form-urlencoded", which is fine for most cases.
+ *
+ * (Boolean) processData - By default, data passed in as an object other as string
+ * will be processed and transformed into a query string, fitting to the default
+ * content-type "application/x-www-form-urlencoded". If you want to send DOMDocuments,
+ * set this option to false.
+ *
+ * (Boolean) async - By default, all requests are send asynchronous (set to true).
+ * If you need synchronous requests, set this option to false.
+ *
+ * (Function) beforeSend - A pre-callback to set custom headers etc., the
+ * XMLHttpRequest is passed as the only argument.
+ *