Creating Searchable Documents

Another extensible form of an HTML link that does not use the <a> tag is one that causes the server to search a database for a document that contains a user-specified keyword or words. An HTML document that contains such a link is known as a searchable document.

The <isindex> Tag (Deprecated)

Before it was deprecated in both the HTML 4 and XHTML standards, authors used to use the <isindex> tag to pass keywords along with a search engine’s URL to the server. The server then matched the keywords against a database of terms to select the next document for display. Today’s authors mostly use forms to pass information to the server and supporting programs. See Chapter 9 for details.

<isindex>

Function

Indicates that a document can be searched

Attributes

action (), class, dir, id, lang, prompt, style, title

End tag

None in HTML; </isindex> or <isindex ... /> in XHTML

Contains

Nothing

Used in

head_content

When a browser encounters the <isindex> tag, it adds a standard search interface to the document (rendered by Internet Explorer in Figure 6-8):

<html>
<head>
<title>Kumquat Advice Database</title>
<base href="cgi-bin/quat-query">
<isindex>
</head>
<body>
<h3>Kumquat Advice Database</h3>
<p>
Search this database to learn more about kumquats!
</body>
</html>
A searchable document

Figure 6-8. A ...

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