You are able to set a default value for the media type charset parameter (the name of a character encoding) to be added to a response if and only if the response's content-type is either text/plain or text/html. 

To do this, simply create a file named ".htaccess" within your webspace, and add the following line: 

AddDefaultCharset <charset> 

A setting of "AddDefaultCharset Off" disables this functionality. Usually, this will mean the exact behavior is dependent on the user's client configuration.