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Tony Johnson 8/12/97 WSC meeting
The Meta Tag Tony Johnson 8/12/97 WSC meeting
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Meta Tag Definition Examples Use of http-equiv Use with Search Engines
Other uses?
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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. <META 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. <META HTTP-EQUIV="Expires" CONTENT="Tue, 20 Aug :25:27 GMT"> will result in the HTTP header: Expires: Tue, 20 Aug :25:27 GMT This can be used by caches to determine when to fetch a fresh copy of the associated document.
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Meta Tag Example Typical HTML page generated by Frontpage
<head> <meta http-equiv="Content-Type” content="text/html; charset=iso "> <meta name="GENERATOR" content="Microsoft FrontPage 2.0"> <title>HEPVIS 98</title> <meta name="FORMATTER" content="Microsoft FrontPage 2.0"> </head> Net effect - zilch
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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 <meta http-equiv=“Expires” content=“Tue, 20 Aug :25:27 GMT”> Redirection of obsolete HTML pages. <meta http-equiv="Refresh" content="2; url=new.html”> Use with frames: <META HTTP-EQUIV="Window-target" CONTENT="_top"> Beware: All uses non-standard and subject to browser/server capabilities.
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Meta Tags with Search Engines
Some search engines (Alta Vista, Infoseek, Harvest?) support the use of Meta tags: e.g. <META NAME="description" CONTENT="Demonstrations Of Advanced HTML"> <META NAME="keywords" CONTENT="HTML,Advanced,Search,Floating Frames"> <META 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.
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References HTML 3.2 reference at w3c Advanced HTML
Advanced HTML Info on META tag (detailed)
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