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HTML <isindex> Tag

The <isindex> defines search string in the current document. The tag isn’t supported by browsers. Learn what to use instead.

The <isindex> tag was used to define a single-line text input field for search queries in the current document. The tag is placed inside the <head> element.

Danger

The <isindex> is a deprecated HTML tag that is obsolete in the HTML specification and unsupported by modern browsers. To define a single-line input field, use the <input> tag with the <label> tag.

Modern Alternative

To create a search input field today, use a <form> with an <input type="search">:

<form action="/search" method="get">
  <label for="search">Search:</label>
  <input type="search" id="search" name="q" placeholder="Search a text">
  <button type="submit">Go</button>
</form>

The <isindex> tag wasn’t implemented consistently across browsers in previous versions of HTML, and it has been obsolete since then. When placed inside <head>, the browser would interpret it as a directive to provide a search function for the document. However, modern browsers already include a built-in Find feature, making this tag unnecessary.

Syntax

The <isindex> tag is void, which means that a closing tag isn’t required. However, in XHTML, the <isindex> tag must be self-closed (<isindex />).

Example of the HTML <isindex> tag:

HTML <isindex> tag

<!DOCTYPE html>
<html>
  <head>
    <isindex prompt="Search a text" />
  </head>
</html>
Try it Yourself »

Attributes

AttributeValueDescription
prompthint-textSpecifies the text string displayed in front of the search query input field. If omitted, the browser displays its own default text.
actionURLSpecifies the URL to which the form data is submitted.

The <isindex> tag supports the Global Attributes and the Event Attributes.

Practice

Practice

What is true about the HTML <isindex> tag based on the information presented at www.w3docs.com?