diff --git a/Lib/BaseHTTPServer.py b/Lib/BaseHTTPServer.py
index f8a1138..fbb8108 100644
--- a/Lib/BaseHTTPServer.py
+++ b/Lib/BaseHTTPServer.py
@@ -77,7 +77,7 @@
 import mimetools
 import SocketServer
 
-# Default error message
+# Default error message template
 DEFAULT_ERROR_MESSAGE = """\
 <head>
 <title>Error response</title>
@@ -90,6 +90,8 @@
 </body>
 """
 
+DEFAULT_ERROR_CONTENT_TYPE = "text/html;charset=utf-8"
+
 def _quote_html(html):
     return html.replace("&", "&amp;").replace("<", "&lt;").replace(">", "&gt;")
 
@@ -217,6 +219,9 @@
     # where each string is of the form name[/version].
     server_version = "BaseHTTP/" + __version__
 
+    error_message_format = DEFAULT_ERROR_MESSAGE
+    error_content_type = DEFAULT_ERROR_CONTENT_TYPE
+
     def parse_request(self):
         """Parse a request (internal).
 
@@ -356,14 +361,12 @@
         content = (self.error_message_format %
                    {'code': code, 'message': _quote_html(message), 'explain': explain})
         self.send_response(code, message)
-        self.send_header("Content-Type", "text/html;charset=utf-8")
+        self.send_header("Content-Type", self.error_content_type)
         self.send_header('Connection', 'close')
         self.end_headers()
         if self.command != 'HEAD' and code >= 200 and code not in (204, 304):
             self.wfile.write(content.encode('UTF-8', 'replace'))
 
-    error_message_format = DEFAULT_ERROR_MESSAGE
-
     def send_response(self, code, message=None):
         """Send the response header and log the response code.