Noindex
Template:Short description Template:Lowercase Template:For The noindex value of an HTML robots meta tag requests that automated Internet bots avoid indexing a web page.<ref name="W3spec">Robots and the META element, Official W3 specification</ref><ref>About the Robots <META> tag</ref> It is also a value of the HTTP response header X-Robots-Tag.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> 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.
Noindexing entire pagesEdit
<syntaxhighlight lang="html"> <html> <head>
<meta name="robots" content="noindex"> <title>Don't index this page</title>
</head> </syntaxhighlight>
Possible values for the meta tag content are: "none", "all", "index", "noindex", "nofollow", and "follow". A combination of the values is also possible,<ref name="W3spec" /> for example: <syntaxhighlight lang="html"> <meta name="robots" content="noindex, follow"> </syntaxhighlight>
Bot-specific directivesEdit
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,<ref name="google_noindex">Using meta tags to block access to your site, Google Webmasters Tools Help</ref> specify: <syntaxhighlight lang="html"> <meta name="googlebot" content="noindex"> </syntaxhighlight>
Or, to block Bing's bot, specify: <syntaxhighlight lang="html"> <meta name="bingbot" content="noindex"> </syntaxhighlight>
Or, to block Baidu's bot, specify: <syntaxhighlight lang="html"> <meta name="baiduspider" content="noindex"> </syntaxhighlight>
robots.txt fileEdit
A robots.txt file can be used to block crawling.
Noindexing part of a pageEdit
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> tagEdit
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:<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> <syntaxhighlight lang="html">
Do index this text. <noindex>Don't index this text.</noindex> Don't index this text.
</syntaxhighlight>
Other indexing spiders also recognize the <noindex> tag, including Atomz.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}Template:Registration required</ref>
microformatEdit
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:<ref name="microformat">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> <syntaxhighlight lang="html">
Do index this text.
Don't index this text.
Don't index this text.
</syntaxhighlight>
A combination of values is also possible,<ref name="microformat" /> for example: <syntaxhighlight lang="html">
</syntaxhighlight>
Yahoo!Edit
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:<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> <syntaxhighlight lang="html">
Do index this text.
Don't index this text.
Don't index this text.
</syntaxhighlight>
Edit
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>.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }} </ref>
<syntaxhighlight lang="html">
Do index this text.
</syntaxhighlight>
Structured commentsEdit
Google Search ApplianceEdit
The Google Search Appliance uses structured comments:<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> <syntaxhighlight lang="html">
Do index this text. Don't index this text.
</syntaxhighlight>
Other indexing spiders also use their own structured comments.
See alsoEdit
- Nofollow link attribute
- Robots Exclusion Standard