The noindex value of an HTML robots meta tag requests that automated Internet bots avoid indexing a web page.[1][2] Reasons why one might want to use this meta tag include advising robots not to index a very large database, web pages that are very transitory, web pages that are under development, web pages that one wishes to keep slightly more private, or the printer and mobile-friendly versions of pages. Since the burden of honoring a website's noindex tag lies with the author of the search robot, sometimes these tags are ignored. Also the interpretation of the noindex tag is sometimes slightly different from one search engine company to the next.

Robots noindexNoindexing entire pages

<html>
<head>
  <meta name="robots" content="noindex">
  <title>Don't index this page</title>
</head>

Possible values for the meta tag content are: "none", "all", "index", "noindex", "nofollow", and "follow". A combination of the values is also possible,[1] for example:

<meta name="robots" content="noindex, follow">

Bot-specific directives

The noindex directive can be restricted only to certain bots by specifying a different "name" value in the meta tag. For example, to specifically block Google's bot,[3] specify: 

<meta name="googlebot" content="noindex">

Or, to block Bing's bot, specify: 

<meta name="bingbot" content="noindex">

Or, to block Baidu's bot, specify: 

<meta name="baiduspider" content="noindex">

robots.txt file

A robots.txt file can be used to block crawling.

Noindexing part of a page

It is also possible to exclude part of a Web page, for example navigation text, from being indexed rather than the whole page. There are various techniques for doing this; it is possible to use several in combination. Google's main indexing spider, Googlebot, is not known to recognize any of these techniques.

<noindex> tag

The Russian search engine Yandex introduced a new <noindex> tag which prevents indexing of the content between the tags. To allow the source code to validate, <!--noindex--> alternatively can be used:[4]

<p>
Do index this text.
<noindex>Don't index this text.</noindex>
<!--noindex-->Don't index this text.<!--/noindex-->
</p>

Other indexing spiders also recognize the <noindex> tag, including Atomz.[5]

microformat

There is a 2005 draft microformats specification with the same functionality. The Robot Exclusion Profile looks for the attribute and value class="robots-noindex" in HTML tags:[6]

<p>Do index this text.</p>
<div class="robots-noindex">Don't index this text.</div>
<span class="robots-noindex">Don't index this text.</span>
<p class="robots-noindex">Don't index this text.</p>

A combination of values is also possible,[6] for example:

<div class="robots-noindex robots-follow">Text.</div>

Yahoo!

In 2007, Yahoo! introduced similar functionality to the microformat into its spider. However, Yahoo!'s spider is incompatible in that it looks for the value class="robots-nocontent" and only this value:[7]

<p>Do index this text.</p>
<div class="robots-nocontent">Don't index this text.</div>
<span class="robots-nocontent">Don't index this text.</span>
<p class="robots-nocontent">Don't index this text.</p>

SharePoint

SharePoint 2010’s iFilter excludes content inside of a <div> tag with the attribute and value class="noindex". Inner <div>s were initially not excluded, but this may have changed. It is also unknown whether the attribute can be applied to tags other than <div>.[8]

<p>Do index this text.</p>
<div class="noindex">Don't index this text.</div>

Structured comments

Google Search Appliance

The Google Search Appliance uses structured comments:[9]

<p>
Do index this text.
<!--googleoff: all-->
Don't index this text.
<!--googleon: all-->
</p>

Other indexing spiders also use their own structured comments.

See also

References

  1. 1 2 Robots and the META element, Official W3 specification
  2. ↑ About the Robots <META> tag
  3. ↑ Using meta tags to block access to your site, Google Webmasters Tools Help
  4. ↑ "Using HTML tags". webmaster → help. Yandex. Section: <noindex> tag. Retrieved March 25, 2013.
  5. ↑ "General Search FAQ". Help. Atomz. 2013. Section: How do I exclude parts of my site from being searched?. Archived from the original on December 8, 2021. Retrieved March 23, 2013. Need to prevent parts of individual pages from being searched? If you want to exclude portions of a page from indexing, surround the text with <noindex> and </noindex> tags. This is useful, for example, if you want to exclude navigation text from searches.(registration required)
  6. 1 2 Janes, Peter (June 18, 2005). "Robot Exclusion Profile". Microformats. Retrieved March 24, 2013.
  7. ↑ Garg, Priyank (May 2, 2007). "Introducing Robots-Nocontent for Page Sections". Yahoo! Search Blog. Yahoo!. Archived from the original on August 20, 2014. Retrieved March 23, 2013.
  8. ↑ "Control Search Indexing (Crawling) Within a Page with Noindex". Microsoft Developer. Microsoft. June 7, 2010. Archived from the original on November 4, 2017. Retrieved November 4, 2017.
  9. ↑ "Administering Crawl: Preparing for a Crawl". Google Search Appliance. Google Inc. August 23, 2012. Section: Excluding Unwanted Text from the Index. Archived from the original on November 23, 2012. Retrieved March 23, 2013.
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