The Meta Tag

Tony Johnson

8/12/97

WSC meeting

Meta Tag

• Definition

• Examples

• Use of http-equiv

• Use with Search Engines

• Other uses?

Meta Tag Definition (from W3C)

• The META element can be used to include name/value pairs describing properties of the document, such as author, expiry date, a list of key words etc. The NAME attribute specifies the property name while the CONTENT attribute specifies the property value, e.g.

• < NAME="Author" CONTENT="Dave Raggett">

• The HTTP-EQUIV attribute can be used in place of the NAME attribute and has a special significance when documents are retrieved via the Hypertext Transfer Protocol (HTTP). HTTP servers may use the property name specified by the HTTP-EQUIV attribute to create an RFC 822 style header in the HTTP response. This can't be used to set certain HTTP headers though, see the HTTP specification for details.

• < HTTP-EQUIV="Expires" CONTENT="Tue, 20 Aug 1996 14:25:27 GMT">

• will result in the HTTP header:

• Expires: Tue, 20 Aug 1996 14:25:27 GMT

• This can be used by caches to determine when to fetch a fresh copy of the associated document.

Meta Tag Example

• Typical HTML page generated by Frontpage

• <>

• < http-equiv="Content-Type”

• content="text/html; charset=iso-8859-1">

• < name="GENERATOR" content="Microsoft FrontPage 2.0">

• <> 98</title>

• < name="FORMATTER" content="Microsoft FrontPage 2.0">

• </head>

• Net effect - zilch

Meta tag with http-equiv

• Any http tag can be specified using meta tag, but not many very useful.

• Don’t use in cgi scripts - specify http header directly.

• Preventing pages which may changed from being cached
  • < http-equiv=“Expires” content=“Tue, 20 Aug 1996 14:25:27 GMT”>

• Redirection of obsolete HTML pages.
  • < http-equiv="Refresh" content="2; url=new.html”>

• Use with frames:
  • < HTTP-EQUIV="Window-target" CONTENT="_top">

• Beware: All uses non-standard and subject to browser/server capabilities.

Meta Tags with Search Engines

• Some search engines (Alta Vista, Infoseek, Harvest?) support the use of Meta tags: e.g.

• < NAME="description" CONTENT="Demonstrations Of Advanced HTML">

• < NAME="keywords" CONTENT="HTML,Advanced,Search,Floating Frames">

• < NAME="robots" CONTENT=”noindex,nofollow”>

• Because these tags are non standard and widely abused some search engines ignore them totally, and others will ignore them if, for example, they contain many or repeated keywords.

References

• HTML 3.2 reference at w3c
  • http://www.w3.org/TR/REC-html32.html#meta

• Advanced HTML
  • http://www.dananeda.demon.co.uk/html/advancedhtml.htm#Meta

• Info on META tag (detailed)
  • http://vancouver-webpages.com/META/