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<isindex>

Obsolete
This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.

<isindex> was an obsolete HTML element that put a text field in a page for querying the document. <isindex> provided a single line text input for entering a query string. When sent, the server would return a list of pages matching the query. Its support depended on both the browser and the server to react to the query.

<isindex> is removed HTML Standard. It was deprecated in HTML 4.01. The same behaviour can be achieved with an HTML form. All major browsers have now removed <isindex>.

Attributes

Like all other HTML elements, this element accepted the global attributes.

prompt: This attribute added its value as a prompt for text field.
action: This attribute determined the server URL to which the query was sent.

Example

<head>
  <isindex prompt="Search Document..." action="/search">
</head>

In past browsers, this would generate, at parse time, a DOM tree equivalent to the following HTML:

<form action="/search">
  <hr>
  <label>
    Search Document...
    <input name="isindex">
  </label>
  <hr>
</form>

History

On June 1992, Dan Connolly would prefer a different anchor type instead of isindex.

On November 1992, indexes as links rather than documents started by Dan Connolly who is pushing the idea that indexes are more links than documents. In this thread, different type of solutions are proposed. The question of forms for making queries is mentioned in reference to Dynatext browser: "The browser displays toggle buttons, text fields etc. The user fills in the fields, clicks OK, and the query results come up in the table of contents window."

A thread about isindex in November 1992, Kevin Hoadley questioned the need for an isindex element and proposed to drop it. He proposed to have instead an input element (idea supported by Steve Putz). Tim Berners-Lee explains the purpose of isindex resulting in aggregated search results. Kevin replies that he doesn't like the boolean nature of isindex and would prefer a system where everything is searchable and proposes to extend the current WWW Framework with a specific httpd configuration and defined that some URIs mapping create search queries.

In 2016, after it was removed from Edge and Chrome, it was proposed to remove isindex from the standard; this removal was completed the next day, after which Safari and Firefox also removed support.

HTML Reference

The HTML Standard classifies it as a obsolete and non-conforming feature.
ISINDEX element deprecated in HTML 4.01
ISINDEX in HTML 3.2
ISINDEX in HTML 2.0 as well the description of the behavior in Queries and Indexes (HTML 2.0)
ISINDEX in HTML+

Browser compatibilityUpdate compatibility data on GitHub

	Desktop
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari
`isindex`	No	No	No	No	No	No
`action`	No	No	No	No	No	No
`prompt`	No	No	No	No	No	No