Editing Meta element (section)

==HTTP message headers==
Meta elements of the form <code>&lt;meta http-equiv="foo" content="bar"></code> can be used as alternatives to HTTP headers. For example, <code>&lt;meta http-equiv="expires" content="Wed, 21 June 2006 14:25:27 GMT"></code> would tell the browser that the page "expires" on June 21, 2006 at 14:25:27 GMT and that it may safely cache the page until then. The [[HTML|HTML 4.01]] specification optionally allows this tag to be parsed by [[HTTP server]]s and set as part of the HTTP response headers,<ref name="HTML 4.01 specification">W3C Recommendation (December 24, 1999), [http://www.w3.org/TR/html401/struct/global.html#h-7.4.4.2 HTML 4.01 Specification]. ''W3.org'', retrieved July 24, 2012</ref> but no web servers currently implement this behavior.<ref name="http-equiv HTML5">[[Stack Overflow]], [https://stackoverflow.com/questions/5236900/meta-http-equiv-is-it-sent-as-part-of-an-http-header-or-does-the-client-parse meta http-equiv – is it sent as part of an HTTP header, or does the client parse the body for meta tags?], from a London Web Standards tech talk.</ref> Instead, the user agent emulates the behavior for some HTTP headers as if they had been sent in the response header itself.