Reference: *Metainformation Module at the W3C
The Metainformation Module declares the
meta element
which is used, within the head
element, in order to associate metainformation with the document.
If the meta element's
name
attribute is used then the value of the
content
attribute is associated with that name (the
scheme
attribute may be used to clarify to which metainformation scheme that particular parameter
belongs).
Alternatively, the
meta element's
http-equiv
attribute may be used to specify a particular
HTTP header name (e.g. Content-Type).
The content
attribute should then be set to the required content of that header.
Such a meta element should
then be interpreted by a user agent as if the equivalent HTTP header were actually
sent by the server for that document. It is better if the server sends the
appropriate header in the first place, but having said that, the meta
technique is useful for those documents which are not being delivered from a web
server.