META tag information

An HTML document consists of two parts. The body of the document contains the content in HTML markup. An often-overlooked part of the HTML document is the "head", which contains metadata ( information about the document). Below is a list of the most useful HTML elements that can be used in the head part of an HTML document.

TITLE

The TITLE element is probably the most well-known. It is used to indicate the title of the current document, which is usually shown in the top of the browser window. It may not contain tags, but may contain HTML entities.

BASE HREF="absolute URL"

The BASE element indicates which URL the browser should assume the document is at. Using BASE is only necessary when the URL used to retrieve the document is not the correct one. For example, a document may be mirrored on another site, or a document may be accessible via more than one URL. In such a case, this tag can be used to indicate the correct URL.

The value for the HREF attribute should be an absolute URL. Relative URLs will produce undefined results.

ISINDEX

The ISINDEX element is an old-fashioned way to indicate a server has the capability to search the current document. Browsers which support this can now let the user specify one or more keywords, which are then sent to the server. The server can then perform the search.

Today it is recommended to use an HTML input form instead.

Note that the server must have the capability to perform searches. Simply adding ISINDEX in the document will not turn your server into a search engine.

LINK REL|REV HREF="some URL"

The LINK element is used to indicate relationships between documents. There are two possible relationships. REL indicates how the current document is related to the document specified in the URL. REV indicates a reverse relationship. In other words, the other document has the indicated relationship with this one.

Some possible values:

The following LINK tags allow advanced browsers to automatically generate a navigational buttonbar for the site. For each possible value, the URL can be either absolute or relative.

META HTTP-EQUIV|NAME CONTENT

The META element is used to convey meta-information about the document, but can also be used to specify headers for the document. By using HTTP-EQUIV, a server should use the name indicated as a header, with the specified CONTENT as its value. For example, these elements could be used:

<META HTTP-EQUIV="Expires" CONTENT="Tue, 04 Dec 1993 21:29:02 GMT">
<META HTTP-EQUIV="Keywords" CONTENT="Nanotechnology, Biochemistry">
<META HTTP-EQUIV="Reply-to" CONTENT="dsr@w3.org (Dave Raggett)">

The server should include the following response headers when the document is requested. Unfortunately this is not well-supported.

Expires: Tue, 04 Dec 1993 21:29:02 GMT
Keywords: Nanotechnology, Biochemistry
Reply-to: dsr@w3.org (Dave Raggett)

Popular uses for META include: