The Isindex element tells the HTML user agent that the document is an index document. As well as reading it, the reader may use a keyword search.

The document can be queried with a keyword search by adding a question mark to the end of the document address, followed by a list of keywords separated by plus signs.

NOTE : The Isindex element is usually generated automatically by a server. If added manually to a HTML document, the HTML user agent assumes that the server can handle a search on the document. To use the Isindex element, the server must have a search engine that supports this element.

To the <ISINDEX> element Netscape authors have added the PROMPT attribute.

PROMPT was introduced by Netscape authors so that text, chosen by the author, can be placed before the text input field of the index. This allows any author chosen message to replace the default text of : This is a searchable index. Enter search keywords

The syntax is:

<ISINDEX PROMPT="Any_text_string : ">

where "Any_text_string" is the text that the user wishes to be displayed before the input box.

Another Netscape specific attribute is ACTION. When used in the <ISINDEX> element, it specifies the cgi script or program to which the text string in the input box should be passed.

<ISINDEX ACTION="websearch">

would pass the text entered into the input box on the page to the cgi script "websearch".

NOTE : "websearch" in the above example is a hypothetical cgi script. If used, the ACTION attribute must point to a properly configured script on the host machine. ACTION is Netscape specific.

Note : <ISINDEX> is no longer supported by Internet Explorer from version 4.0.