Syntax: status_format json;status_format jsonp [callback]; Default: status_format json; Context: http, server, location
By default, status information is output in the JSON format.
Alternatively, data may be output as JSONP. The callback parameter specifies the name of a callback function. The value can contain variables. If parameter is omitted, or the computed value is an empty string, then “ngx_status_jsonp_callback” is used.