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4.5.1 HREF in Anchors

As mentioned previously, anchors mark the beginning or end of hypertext links. The HREF attribute (which is optional) marks the anchor as the start of a link to another document, or to a particular place in another document.

The address of the referenced document is specified by an absolute or relative URL:

<A HREF="URL"> anchor </A>

Where `URL' (Universal Resource Locator) is the URL of the document to be accessed. For example HREF can use http to access other HTML documents, images, etc. or it can use ftp or gopher. It can even indicate a telnet connection. See the URL document for more information on thee possibilities.

`Relative' URLs are also possible when accessing http servers. These are convenient for referencing documents from the same http server as the current document. In this case you need only specify the location of the document relative to the current one. Here are some examples of the varied possibilities:

http://www.web.edu/u1/stuff/doc.html: HTML document served by the specified http server.
ftp://ftp.nccc.edu/pub/doc/blob.tar.Z: Compressed tar file accessed via anonymous ftp from the indicated site.
../../OtherStuff/thing.html: A relative URL: the HTML document comes from the same http server but in the directory OtherStuff, found two levels up from the directory the current document was served from.
telnet://flober.rodent.edu: A telnet session to the indicated machine.

Links to a Particular Place in a Document

Particular places in an HTML document can be marked as specific destinations of hypertext links via the NAME attribute. For example, suppose a place in a document is marked via

<A NAME="proj1">Project 1</A>

From within this document we can create a hypertext link to this place by specifying the anchor:

<A HREF="#proj1">(see Project 1)</A>

If we wanted to reference this place from another document in the same directory we would put

<A HREF="doc.html#proj1">(see Project 1)</A>

and so on.

Special http URLs

HTTP Servers often allocate special URLs for specific types of files. The most important one is /cgi-bin. This is used to reference the `server scripts' directory -- this is the directory that contains scripts and programs that can be accessed from the browsers, via an HREF. For example, to access the script `phone' (which scans a phonebook for particular names) on the machine `www.foo.com' via http, the HREF is

HREF="http://www.foo.com/cgi-bin/phone"

For more information look at Section 6; you should also consult you local httpd server documentation.

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