Meta
Meta (from the Greek μετά, '' meta'', meaning "after" or "beyond") is a prefix meaning "more comprehensive" or "transcending".
In modern nomenclature, ''meta''- can also serve as a prefix meaning self-referential, as a field of study or ende ...
elements are tags used in
HTML
The HyperText Markup Language or HTML is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScri ...
and
XHTML
Extensible HyperText Markup Language (XHTML) is part of the family of XML markup languages. It mirrors or extends versions of the widely used HyperText Markup Language (HTML), the language in which Web pages are formulated.
While HTML, prior ...
documents to provide structured
metadata
Metadata is "data that provides information about other data", but not the content of the data, such as the text of a message or the image itself. There are many distinct types of metadata, including:
* Descriptive metadata – the descriptive ...
about a
Web page.
They are part of a web page's
head
section. Multiple Meta elements with different
attribute
Attribute may refer to:
* Attribute (philosophy), an extrinsic property of an object
* Attribute (research), a characteristic of an object
* Grammatical modifier, in natural languages
* Attribute (computing), a specification that defines a prope ...
s can be used on the same page. Meta elements can be used to specify page description, keywords and any other
metadata
Metadata is "data that provides information about other data", but not the content of the data, such as the text of a message or the image itself. There are many distinct types of metadata, including:
* Descriptive metadata – the descriptive ...
not provided through the other
head
elements and attributes.
The meta element has two uses: either to emulate the use of an
HTTP response header field
The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, w ...
, or to embed additional metadata within the HTML document.
With HTML up to and including
HTML 4.01
The HyperText Markup Language or HTML is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScript ...
and XHTML, there were four valid attributes:
content
,
http-equiv
,
name
and
scheme
. Under
HTML 5
HTML5 is a markup language used for structuring and presenting content on the World Wide Web. It is the fifth and final major HTML version that is a World Wide Web Consortium (W3C) recommendation. The current specification is known as the HTML ...
,
charset
has been added and
scheme
has been removed.
http-equiv
is used to emulate an HTTP header, and
name
to embed metadata. The value of the statement, in either case, is contained in the
content
attribute, which is the only required attribute unless
charset
is given.
charset
is used to indicate the character set of the document, and is available in HTML5.
Such elements must be placed as tags in the
head
section of an
HTML
The HyperText Markup Language or HTML is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScri ...
or
XHTML
Extensible HyperText Markup Language (XHTML) is part of the family of XML markup languages. It mirrors or extends versions of the widely used HyperText Markup Language (HTML), the language in which Web pages are formulated.
While HTML, prior ...
document.
Examples of the meta
element
meta
elements can specify
HTTP
The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, ...
headers which should be sent before the actual content when the HTML page is served from the web server to the client. For example:
as an alternative to the response header
Content-Type:
to indicate the
media type
A media type (also known as a MIME type) is a two-part identifier for file formats and format contents transmitted on the Internet. The Internet Assigned Numbers Authority (IANA) is the official authority for the standardization and publication o ...
and, more commonly needed, the
UTF-8
UTF-8 is a variable-width encoding, variable-length character encoding used for electronic communication. Defined by the Unicode Standard, the name is derived from ''Unicode'' (or ''Universal Coded Character Set'') ''Transformation Format 8-bit'' ...
character encoding
Character encoding is the process of assigning numbers to Graphics, graphical character (computing), characters, especially the written characters of Language, human language, allowing them to be Data storage, stored, Data communication, transmi ...
.
Meta tags can be used to describe the contents of the page:
In this example, the
meta
element describes the contents of a web page.
Meta element used in search engine optimization
Meta elements provide information about the web page, which can be used by search engines to help categorize the page correctly.
They have been the focus of a field of
marketing
Marketing is the process of exploring, creating, and delivering value to meet the needs of a target market in terms of goods and services; potentially including selection of a target audience; selection of certain attributes or themes to emph ...
research known as
search engine optimization
Search engine optimization (SEO) is the process of improving the quality and quantity of Web traffic, website traffic to a website or a web page from web search engine, search engines. SEO targets unpaid traffic (known as "natural" or "Organ ...
(SEO), where different methods are used to provide a user's website with a higher ranking on search engines. Prior to the rise of content-analysis by search engines in the mid-1990s (most notably Google), search engines were reliant on metadata to correctly classify a Web page and webmasters quickly learned the commercial significance of having the right meta element. The search engine community is now divided as to the value of meta tags. Some claim they have no value, others that they are central, while many simply conclude there is no clear answer but, since they do no harm, they use them just in case. Google states they do support the meta tags "content", "robots", "google", "google-site-verification", "content-type", "refresh" and "google-bot".
Major search engine robots look at many factors when determining how to rank a page of which meta tags will only form a portion. Furthermore, most search engines change their ranking rules frequently. Google have stated they update their ranking rules every 48 hours. Under such circumstances, a definitive understanding of the role of meta tags in SEO is unlikely.
The keywords
attribute
The
keywords
attribute was popularized by
search engine
A search engine is a software system designed to carry out web searches. They search the World Wide Web in a systematic way for particular information specified in a textual web search query. The search results are generally presented in a ...
s such as
Infoseek
Infoseek (also known as the "big yellow") was an American internet search engine founded in 1994 by Steve Kirsch.
Infoseek was originally operated by the Infoseek Corporation, headquartered in Sunnyvale, California. Infoseek was bought by The Wa ...
and
AltaVista
AltaVista was a Web search engine established in 1995. It became one of the most-used early search engines, but lost ground to Google and was purchased by Yahoo! in 2003, which retained the brand, but based all AltaVista searches on its own sear ...
in 1995, and its popularity quickly grew until it became one of the most commonly used
meta
elements.
No consensus exists whether or not the
keywords
attribute has any effect on ranking at any of the major
search engines
A search engine is a software system designed to carry out web searches. They search the World Wide Web in a systematic way for particular information specified in a textual web search query. The search results are generally presented in a ...
today. It is speculated that it does if the keywords used in the
meta
can also be found in the page copy itself. With respect to
Google
Google LLC () is an American multinational technology company focusing on search engine technology, online advertising, cloud computing, computer software, quantum computing, e-commerce, artificial intelligence, and consumer electronics. ...
, thirty-seven leaders in search engine optimization concluded in April 2007 that the relevance of having keywords in the
meta
-attribute
keywords
is little to none and in September 2009
Matt Cutts
Matthew Cutts (born 1972 or 1973) is an American software engineer. Cutts is the former Administrator of the United States Digital Service. He was first appointed as acting administrator, to later be confirmed as full administrator in October 201 ...
of Google announced that they were no longer taking keywords into account whatsoever. However, both these articles suggest that
Yahoo!
Yahoo! (, styled yahoo''!'' in its logo) is an American web services provider. It is headquartered in Sunnyvale, California and operated by the namesake company Yahoo Inc., which is 90% owned by investment funds managed by Apollo Global Man ...
still makes use of the keywords meta tag in some of its rankings. Yahoo! itself claims support for the keywords meta tag in conjunction with other factors for improving search rankings. In October 2009 Search Engine Round Table announced that "Yahoo Drops The Meta Keywords Tag Also" but later reported that the announcement made by Yahoo!'s Senior Director of Search was incorrect.
["Yahoo's Senior Director of Search Got It Wrong, Yahoo Uses Meta Keywords Still"](_blank)
SEO Roundtable, October 16, 2009, Retrieved April 22, 2011 In the corrected statement Yahoo! Senior Director of Search states that "…What changed with Yahoo's ranking algorithms is that while we still index the meta keyword tag, the ranking importance given to meta keyword tags receives the lowest ranking signal in our system … it will actually have less effect than introducing those same words in the body of the document, or any other section."
In Sept 2012, Google announced that they will consider Keyword Meta tag for news publishers.
Google
Google LLC () is an American multinational technology company focusing on search engine technology, online advertising, cloud computing, computer software, quantum computing, e-commerce, artificial intelligence, and consumer electronics. ...
said that this may help worthy content to get noticed. The syntax of the news meta keyword has subtle difference from custom keyword meta tag; it is denoted by "news_keywords", while the custom keyword meta tag is denoted by "keywords". Google News no longer takes into account keywords announced by news_keywords.
The Title attribute
According to Moz, "Title tags are the second most important on-page factor for SEO, after content". They convey to the search engines what a given page is all about. It used to be standard SEO practice to include the primary and the secondary keywords in the title for better ranking. Google has gone through various iterations of showing short or longer amounts of content from within the title tags.
Regardless, the title tags still hold importance in three different ways.
* They are displayed as page title in search results (and influence user behavior with respect to clicking on particular results).
* Web browsers display them in naming open tabs; since the title is visible on hover, this is especially useful when too many tabs are open and only the
favicon
A favicon (; short for favorite icon), also known as a shortcut icon, website icon, tab icon, URL icon, or bookmark icon, is a file containing one or more small icons, associated with a particular website or web page. A web designer can create s ...
for each page (if available) is visible.
* As in search results, titles are visible when page links are posted on social media and this, too, conveys to the users what the link is about.
The description
attribute
Unlike the
keywords
attribute, the
description
attribute is supported by most major search engines, like
Yahoo!
Yahoo! (, styled yahoo''!'' in its logo) is an American web services provider. It is headquartered in Sunnyvale, California and operated by the namesake company Yahoo Inc., which is 90% owned by investment funds managed by Apollo Global Man ...
and
Bing
Bing most often refers to:
* Bing Crosby (1903–1977), American singer
* Microsoft Bing, a web search engine
Bing may also refer to:
Food and drink
* Bing (bread), a Chinese flatbread
* Bing (soft drink), a UK brand
* Bing cherry, a variety ...
, while
Google
Google LLC () is an American multinational technology company focusing on search engine technology, online advertising, cloud computing, computer software, quantum computing, e-commerce, artificial intelligence, and consumer electronics. ...
will fall back on this tag when information about the page itself is requested (e.g. using the
related:
query). The
description
attribute provides a concise explanation of a
Web page's content. This allows the Web page authors to give a more meaningful description for listings than might be displayed if the search engine was unable to automatically create its own description based on the page content. The description is often, but not always, displayed on
search engine results page
Search Engine Results Pages (SERP) are the pages displayed by search engines in response to a query by a user. The main component of the SERP is the listing of results that are returned by the search engine in response to a keyword query. The pa ...
s, so it can affect click-through rates. While clicks for a result can be a positive sign of effective
title
and
description
writing,
Google
Google LLC () is an American multinational technology company focusing on search engine technology, online advertising, cloud computing, computer software, quantum computing, e-commerce, artificial intelligence, and consumer electronics. ...
does not recognize this meta element as a ranking factor, so using target keyword phrases in that element will not help a site rank better. W3C doesn't specify the size of this description meta tag, but almost all search engines recommend it to be shorter than 160 characters of plain text.
The language
attribute
The
language
attribute tells search engines what natural language the website is written in (e.g. English, Spanish or French), as opposed to the coding language (e.g. HTML). It is normally an
IETF language tag
An IETF BCP 47 language tag is a standardized code or tag that is used to identify human languages in the Internet. The tag structure has been standardized by the Internet Engineering Task Force (IETF) in ''Best Current Practice (BCP) 47''; the su ...
for the language name. It is of most use when a website is written in multiple languages and can be included on each page to tell search engines in which language a particular page is written. User-agents can (and do) use language information to select language-appropriate fonts, which improves the overall user experience of the page.
The robots
attribute
The
robots
attribute, supported by several major search engines, controls whether search engine spiders are allowed to
index
Index (or its plural form indices) may refer to:
Arts, entertainment, and media Fictional entities
* Index (''A Certain Magical Index''), a character in the light novel series ''A Certain Magical Index''
* The Index, an item on a Halo megastru ...
a page, or not, and whether they should follow links from a page, or not. The attribute can contain one or more comma-separate values. The
noindex
value prevents a page from being indexed, and
nofollow
prevents links from being
crawled. Other values recognized by one or more search engines can influence how the engine indexes pages, and how those pages appear on the search results. These include
noarchive
, which instructs a search engine not to store an archived copy of the page, and
nosnippet
, which asks that the search engine not include a snippet from the page along with the page's listing in search results.
Meta tags are one of the best options for preventing search engines from indexing content of a website.
Additional attributes for search engines
=NOODP
=
The search engines
Google
Google LLC () is an American multinational technology company focusing on search engine technology, online advertising, cloud computing, computer software, quantum computing, e-commerce, artificial intelligence, and consumer electronics. ...
,
Yahoo!
Yahoo! (, styled yahoo''!'' in its logo) is an American web services provider. It is headquartered in Sunnyvale, California and operated by the namesake company Yahoo Inc., which is 90% owned by investment funds managed by Apollo Global Man ...
and
MSN
MSN (meaning Microsoft Network) is a web portal and related collection of Internet services and apps for Windows and mobile devices, provided by Microsoft and launched on August 24, 1995, alongside the release of Windows 95.
The Microsoft Net ...
used in some cases the title and abstract of the
DMOZ
DMOZ (from ''directory.mozilla.org'', an earlier domain name, stylized in lowercase in its logo) was a multilingual open-content directory of World Wide Web links. The site and community who maintained it were also known as the Open Directory ...
(aka Open Directory Project) listing of a website for the title and/or description (also called snippet or abstract) in the
search engine results page
Search Engine Results Pages (SERP) are the pages displayed by search engines in response to a query by a user. The main component of the SERP is the listing of results that are returned by the search engine in response to a keyword query. The pa ...
s (SERP). To give
webmaster
A webmaster is a person responsible for maintaining one or more websites. The title may refer to web architects, web developers, site authors, website administrators, website owners, website coordinators, or website publishers.
The duties of ...
s the option to specify that the Open Directory Project content should not be used for listings of their website, Microsoft introduced in May 2006 the new "
NOODP
" value for the "
robots
" element of the meta tags. Google followed in July 2006 and Yahoo! in October 2006.
By 2017, Google reported stopping the use of
DMOZ
DMOZ (from ''directory.mozilla.org'', an earlier domain name, stylized in lowercase in its logo) was a multilingual open-content directory of World Wide Web links. The site and community who maintained it were also known as the Open Directory ...
, following its closure, hence, NOODP directive is ignored since.
The syntax is the same for all search engines who support the tag.
Webmasters can decide if they want to disallow the use of their ODP listing on a per search engine basis
Google:
Yahoo!
MSN and Live Search (via
bingbot
Bingbot is a web-crawling robot (type of internet bot), deployed by Microsoft October 2010 to supply Bing. It collects documents from the web to build a searchable index for the Bing (search engine). It performs the same function as Google's '' G ...
, previously
msnbot Msnbot was a web-crawling robot (type of internet bot), deployed by Microsoft to collect documents from the web to build a searchable index for the MSN Search engine. It went into beta in 2004, and had full public release in 2005. The month of Octo ...
):
=NOYDIR
=
Yahoo! puts content from their own Yahoo! directory next to the ODP listing. In 2007 they introduced a meta tag that lets web designers opt-out of this.
Adding the
NOYDIR
tag to a page will prevent Yahoo! from displaying
Yahoo! Directory
The Yahoo! Directory was a web directory which at one time rivaled DMOZ in size. The directory was Yahoo!'s first offering and started in 1994 under the name Jerry and David's Guide to the World Wide Web. When Yahoo! changed its main results to c ...
titles and abstracts.
Academic studies
Google
Google LLC () is an American multinational technology company focusing on search engine technology, online advertising, cloud computing, computer software, quantum computing, e-commerce, artificial intelligence, and consumer electronics. ...
does not use HTML keyword or meta tag elements for indexing. The Director of Research at Google,
Monika Henzinger
Monika Henzinger (born as Monika Rauch, 17 April 1966 in Weiden in der Oberpfalz) is a German computer scientist, and is a former director of research at Google. She is currently a professor at the University of Vienna. Her expertise is mainly o ...
, was quoted (in 2002) as saying, "Currently we don't trust metadata because we are afraid of being manipulated." Other search engines developed techniques to penalize Web sites considered to be "cheating the system". For example, a Web site repeating the same meta keyword several times may have its ranking ''decreased'' by a search engine trying to eliminate this practice, though that is unlikely. It is more likely that a search engine will ignore the meta keyword element completely, and most do regardless of how many words are used in the element.
Google
Google LLC () is an American multinational technology company focusing on search engine technology, online advertising, cloud computing, computer software, quantum computing, e-commerce, artificial intelligence, and consumer electronics. ...
does, however, use meta tag elements for displaying site links. The title tags are used to create the link in search results:
Site name - Page title - Keyword description
The meta description often appears in
Google
Google LLC () is an American multinational technology company focusing on search engine technology, online advertising, cloud computing, computer software, quantum computing, e-commerce, artificial intelligence, and consumer electronics. ...
search results to describe the link:
Additionally, enterprise search startup
Swiftype
Swiftype is a search and index company based in San Francisco, California, that provides search software for organizations, websites, and computer programs. Notable customers include AT&T, Dr. Pepper, Hubspot and TechCrunch.
History
Swiftype was ...
considers meta tags as a mechanism for signaling relevancy for their web site search engines, even introducing their own extension called Meta Tags 2.
Redirects
Meta refresh
Meta refresh is a method of instructing a web browser to automatically refresh the current web page or frame after a given time interval, using an HTML meta element with the http-equiv parameter set to "refresh" and a content parameter giving the ...
elements can be used to instruct a
Web browser
A web browser is application software for accessing websites. When a user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's screen. Browsers are used on ...
to automatically refresh a Web page after a given time interval. It is also possible to specify an alternative
URL
A Uniform Resource Locator (URL), colloquially termed as a web address, is a reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it. A URL is a specific type of Uniform Resource Identifie ...
and use this technique in order to
redirect
Redirect and its variants (e.g., redirection) may refer to:
Arts, entertainment, and media
* ''Redirect'', 2012 Christian metal album and its title track by Your Memorial
* ''Redirected'' (film), a 2014 action comedy film
Computing
* ICMP Re ...
the user to a different location.
Auto refreshing via a META element has been deprecated for more than ten years,
and recognized as problematic before that.
The W3C suggests that user agents should allow users to disable it, otherwise META refresh should not be used by web pages.
For Internet Explorer's security settings, under the miscellaneous category, meta refresh can be turned off by the user, thereby disabling its redirect ability.
In Mozilla Firefox it can be disabled in the configuration file under the key name "accessibility.blockautorefresh".
Accessibility.blockautorefresh
mozillaZine, archived June 2, 2009 fro
the original
/ref>
Many web design tutorials also point out that client-side redirecting tends to interfere with the normal functioning of a Web browser's "back" button. After being redirected, clicking the back button will cause the user to go back to the redirect page, which redirects them again. Some modern browsers seem to overcome this problem however, including Safari
A safari (; ) is an overland journey to observe wild animals, especially in eastern or southern Africa. The so-called "Big Five" game animals of Africa – lion, leopard, rhinoceros, elephant, and Cape buffalo – particularly form an importa ...
, Mozilla Firefox
Mozilla Firefox, or simply Firefox, is a free and open-source web browser developed by the Mozilla Foundation and its subsidiary, the Mozilla Corporation. It uses the Gecko rendering engine to display web pages, which implements current and a ...
and Opera
Opera is a form of theatre in which music is a fundamental component and dramatic roles are taken by singers. Such a "work" (the literal translation of the Italian word "opera") is typically a collaboration between a composer and a librett ...
.
Auto-redirects via markup (versus server-side redirects) are not in compliance with the W3C's - Web Content Accessibility Guidelines (WCAG) 1.0 (guideline 7.5).[W3C Recommendation (May 5, 1999)]
Web Content Accessibility Guidelines 1.0 - Guideline 7
''W3.org'', retrieved September 28, 2007
HTTP message headers
Meta elements of the form <meta http-equiv="foo" content="bar">
can be used as alternatives to HTTP headers. For example, <meta http-equiv="expires" content="Wed, 21 June 2006 14:25:27 GMT">
would tell the browser that the page "expires" on June 21, 2006 at 14:25:27 GMT and that it may safely cache the page until then. The HTML 4.01
The HyperText Markup Language or HTML is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScript ...
specification optionally allows this tag to be parsed by HTTP server
An HTTP server is a computer (software) program (or even a software component included in an other program) that plays the role of a server in a client–server model by implementing the ''server part'' of the HTTP and/or HTTPS network protocol ...
s and set as part of the HTTP response headers,[W3C Recommendation (December 24, 1999)]
HTML 4.01 Specification
''W3.org', retrieved July 24, 2012 but no web servers currently implement this behavior.Stack Overflow
In software, a stack overflow occurs if the call stack pointer exceeds the stack bound. The call stack may consist of a limited amount of address space, often determined at the start of the program. The size of the call stack depends on many fac ...
meta http-equiv - is it sent as part of an HTTP header, or does the client parse the body for meta tags?
from a London Web Standards tech talk. Instead, the user agent emulates the behavior for some HTTP headers as if they had been sent in the response header itself.
Alternative to meta
elements
Some HTML elements and attributes already handle certain pieces of meta data and may be used by authors instead of META to specify those pieces: the TITLE element, the ADDRESS element, the INS and DEL elements, the title attribute, and the cite attribute.
An alternative to meta
elements for enhanced subject access within a website is the use of a back-of-book-style index for the website. See th
American Society of Indexers
website for an example.
In 1994, ALIWEB, also used an index file to provide the type of information commonly found in meta keywords attributes.
In cases where the content attribute's value is a URL, many authors decide to use a link element with a proper value for its rel attribute as well.
For a comparison on when it is best to use HTTP-headers, meta-elements, or attributes in the case of language specification
see here
See also
* Meta refresh
Meta refresh is a method of instructing a web browser to automatically refresh the current web page or frame after a given time interval, using an HTML meta element with the http-equiv parameter set to "refresh" and a content parameter giving the ...
, a deprecated meta element
* RDFa, attribute level extensions to XHTML, for embedding metadata
* Resource Description Framework The Resource Description Framework (RDF) is a World Wide Web Consortium (W3C) standard originally designed as a data model for metadata. It has come to be used as a general method for description and exchange of graph data. RDF provides a variety of ...
(RDF)
References
External links
The element
from the latest published version of HTML, W3C Recommendation
MetaExtensions - WHATWG Wiki
proposals for value of name
attribute.
{{DEFAULTSORT:Meta Element
HTML tags
Web 1.0
Search engine optimization