||Specifies what types of media output the client is prepared
to handle. Often, a client will specify several types of media
that is can handle such as in the following case
Alternatively, a web browser might specify that it is prepared to
handle "any" media using the following line:
||Specifies whether or not the user has permission to access a
||Specifies that the message body is encrypted, compressed,
||Indicates the media type of the information in the message
||Specifies the number of bytes in the message body for requests
with a message body
||Indicates the date and time of a request if the request has a
||Provides the email address of the user using the client if it is
||Tells the server not to deal with the request if the document
has not been modified since a given time.
||Specifies the MIME version used to generate the message
||Contains any additional information that the client wishes
to specify to the server
||Indicates the URL of the page from which the request was made.
(This request header is misspelled in the protocol itself)
||Specifies the name and version number of the web browser
making the request.