JavaScript: The Definitive Guide

25.322. XMLHttpRequest.getAllResponseHeaders( ): return unparsed HTTP response headers

25.322.1. Synopsis

String getAllResponseHeaders( )

25.322.1.1. Returns

If readyState is less than 3, this method returns null. Otherwise, it returns all HTTP response headers (but not the status line) sent by the server. The headers are returned as a single string, with one header per line. Lines are delimited by "\r\n" line terminators.