Links and Webs - HTML and XHTML: The Definitive Guide - page 301

6.2.3.5. The http search parameter
The search component of the http URL, along with its preceding question
mark, is optional. It indicates that the path is a searchable or executable
resource on the server. The content of the search component is passed
to the server as parameters that control the search or execution func-
tion.
The actual encoding of parameters in the search component depends
upon the server and the resource being referenced. We cover the para-
meters for searchable resources later in this chapter, when we discuss
searchable documents. We discuss parameters for executable resources
in Chapter 9 .
Although our initial presentation of http URLs indicated that a URL may
have either a fragment identifier or a search component, some browsers
let you use both in a single URL. If you so desire, you can follow the
search parameter with a fragment identifier, telling the browser to begin
displaying the results of the search at the indicated fragment. Netscape,
for example, supports this usage.
We don't recommend this kind of URL, though. First and foremost, it
doesn't work on all browsers. Just as important, using a fragment im-
plies that you are sure that the results of the search will have a frag-
ment of that name defined within the document. For large document
collections, this is hardly likely. You are better off omitting the fragment,
showing the search results from the beginning of the document, and
avoiding potential confusion among your readers.
6.2.3.6. Sample http URLs
Here are some sample http URLs:
http://www.oreilly.com/catalog.html
http://www.oreilly.com
http://www.kumquat.com:8080