Meta element

Last updated

Meta elements are tags used in HTML and XHTML documents to provide structured metadata about a Web page. They are part of a web page's head section. Multiple Meta elements with different attributes can be used on the same page. Meta elements can be used to specify page description, keywords and any other metadata not provided through the other head elements and attributes. [1]

Contents

The meta element has two uses: either to emulate the use of an HTTP response header field, or to embed additional metadata within the HTML document.

With HTML up to and including HTML 4.01 and XHTML, there were four valid attributes: content, http-equiv, name and scheme. Under HTML 5, 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 or XHTML document.

Examples of the meta element

meta elements can specify HTTP headers which should be sent before the actual content when the HTML page is served from the web server to the client. For example:

<metacharset="utf-8">

as an alternative to the response header Content-Type: to indicate the media type and, more commonly needed, the UTF-8 character encoding.

Meta tags can be used to describe the contents of the page:

<metaname="description"content="The Federal Aviation Administration is an operating mode of the U.S. Department of Transportation.">

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 research known as search engine optimization (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 [2] 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 engines such as Infoseek and AltaVista in 1995, and its popularity quickly grew until it became one of the most commonly used meta elements. [3]

No consensus exists whether or not the keywords attribute has any effect on ranking at any of the major search engines today. It is speculated[ by whom? ] that it does if the keywords used in the meta can also be found in the page copy itself.[ citation needed ] With respect to Google, 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 [4] and in September 2009 Matt Cutts of Google announced that they were no longer taking keywords into account whatsoever. [5] However, both these articles suggest that Yahoo! 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. [6] In October 2009 Search Engine Round Table announced that "Yahoo Drops The Meta Keywords Tag Also" [7] but later reported that the announcement made by Yahoo!'s Senior Director of Search was incorrect. [8] 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." [8] In Sept 2012, Google [9] announced that they will consider Keyword Meta tag for news publishers. Google 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. [10]

The Title attribute

According to Moz, "Title tags are the second most important on-page factor for SEO, after content". [11] 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.

The description attribute

Unlike the keywords attribute, the description attribute is supported by most major search engines, like Yahoo! and Bing, while Google 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 pages, so it can affect click-through rates. While clicks for a result can be a positive sign of effective title and description writing, Google 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.[ citation needed ]

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 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.[ citation needed ]

The robots attribute

The robots attribute, supported by several major search engines, [12] [ failed verification ] controls whether search engine spiders are allowed to index 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. [13]

Meta tags are one of the best options for preventing search engines from indexing content of a website. [14]

Additional attributes for search engines

NOODP

The search engines Google, Yahoo! and MSN used in some cases the title and abstract of the DMOZ (aka Open Directory Project) listing of a website for the title and/or description (also called snippet or abstract) in the search engine results pages (SERP). To give webmasters 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. [15] Google followed in July 2006 [16] and Yahoo! in October 2006. [17]

By 2017, Google reported stopping the use of DMOZ, following its closure, hence, NOODP directive is ignored since. [18]

The syntax is the same for all search engines who support the tag.

<metaname="robots"content="noodp">

Webmasters can decide if they want to disallow the use of their ODP listing on a per search engine basis

Google:

<metaname="googlebot"content="noodp">

Yahoo!

<metaname="Slurp"content="noodp">

MSN and Live Search (via bingbot, previously msnbot): 

<metaname="bingbot"content="noodp">
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. [19]

Adding the NOYDIR tag to a page will prevent Yahoo! from displaying Yahoo! Directory titles and abstracts.

<metaname="robots"content="noydir"><metaname="Slurp"content="noydir">

Effect on Searching

Google does not use HTML keyword or meta tag elements for indexing. The Director of Research at Google, Monika Henzinger, was quoted (in 2002) as saying, "Currently we don't trust metadata because we are afraid of being manipulated." [20] 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 does, however, use meta tag elements for displaying site links. The title tags are used to create the link in search results:

<title>Site name - Page title - Keyword description</title>

The meta description often appears in Google search results to describe the link:

<metaname="description"content="A blurb to describe the content of the page appears here">

Additionally, enterprise search startup Swiftype considers meta tags as a mechanism for signaling relevancy for their web site search engines, even introducing their own extension called Meta Tags 2. [21]

Redirects

Meta refresh elements can be used to instruct a Web browser to automatically refresh a Web page after a given time interval. It is also possible to specify an alternative URL and use this technique in order to redirect the user to a different location. Auto refreshing via a META element has been deprecated for more than ten years, [22] and recognized as problematic before that. [22]

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". [23]

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, Mozilla Firefox and Opera.[ citation needed ]

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). [24]

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 specification optionally allows this tag to be parsed by HTTP servers and set as part of the HTTP response headers, [25] but no web servers currently implement this behavior. [26] 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. [27]

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.[ citation needed ] See the 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.[ undue weight? – discuss ]

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. [27]

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

Related Research Articles

<span class="mw-page-title-main">HTML</span> HyperText Markup Language

HyperText Markup Language (HTML) is the standard markup language for documents designed to be displayed in a web browser. It defines the content and structure of web content. It is often assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScript.

Spamdexing is the deliberate manipulation of search engine indexes. It involves a number of methods, such as link building and repeating unrelated phrases, to manipulate the relevance or prominence of resources indexed in a manner inconsistent with the purpose of the indexing system.

Search engine optimization (SEO) is the process of improving the quality and quantity of website traffic to a website or a web page from search engines. SEO targets unpaid traffic rather than direct traffic or paid traffic. Unpaid traffic may originate from different kinds of searches, including image search, video search, academic search, news search, and industry-specific vertical search engines.

An HTML element is a type of HTML document component, one of several types of HTML nodes. The first used version of HTML was written by Tim Berners-Lee in 1993 and there have since been many versions of HTML. The current de facto standard is governed by the industry group WHATWG and is known as the HTML Living Standard.

<span class="mw-page-title-main">Metasearch engine</span> Online information retrieval tool

A metasearch engine is an online information retrieval tool that uses the data of a web search engine to produce its own results. Metasearch engines take input from a user and immediately query search engines for results. Sufficient data is gathered, ranked, and presented to the users.

Doorway pages are web pages that are created for the deliberate manipulation of search engine indexes (spamdexing). A doorway page will affect the index of a search engine by inserting results for particular phrases while sending visitors to a different page. Doorway pages that redirect visitors without their knowledge use some form of cloaking. This usually falls under Black Hat SEO.

URL redirection, also called URL forwarding, is a World Wide Web technique for making a web page available under more than one URL address. When a web browser attempts to open a URL that has been redirected, a page with a different URL is opened. Similarly, domain redirection or domain forwarding is when all pages in a URL domain are redirected to a different domain, as when wikipedia.com and wikipedia.net are automatically redirected to wikipedia.org.

The noindex value of an HTML robots meta tag requests that automated Internet bots avoid indexing a web page. 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.

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 time interval in seconds. It is also possible to instruct the browser to fetch a different URL when the page is refreshed, by including the alternative URL in the content parameter. By setting the refresh time interval to zero, meta refresh can be used as a method of URL redirection.

The alt attribute is the HTML attribute used in HTML and XHTML documents to specify alternative text that is to be displayed in place of an element that cannot be rendered. The alt attribute is used for short descriptions, with longer descriptions using the longdesc attribute. The standards organization for the World Wide Web, the World Wide Web Consortium (W3C), recommends that every image displayed through HTML have an alt attribute, though the alt attribute does not need to contain text. The lack of proper alt attributes on website images has led to several accessibility-related lawsuits.

A video search engine is a web-based search engine which crawls the web for video content. Some video search engines parse externally hosted content while others allow content to be uploaded and hosted on their own servers. Some engines also allow users to search by video format type and by length of the clip. The video search results are usually accompanied by a thumbnail view of the video.

nofollow is a setting on a web page hyperlink that directs search engines not to use the link for page ranking calculations. It is specified in the page as a type of link relation; that is: <a rel="nofollow" ...>. Because search engines often calculate a site's importance according to the number of hyperlinks from other sites, the nofollow setting allows website authors to indicate that the presence of a link is not an endorsement of the target site's importance.

RDFa or Resource Description Framework in Attributes is a W3C Recommendation that adds a set of attribute-level extensions to HTML, XHTML and various XML-based document types for embedding rich metadata within Web documents. The Resource Description Framework (RDF) data-model mapping enables its use for embedding RDF subject-predicate-object expressions within XHTML documents. It also enables the extraction of RDF model triples by compliant user agents.

A search engine results page (SERP) is a webpage that is displayed by a search engine in response to a query by a user. The main component of a SERP is the listing of results that are returned by the search engine in response to a keyword query.

<span class="mw-page-title-main">Semantic HTML</span> HTML used to reinforce meaning of documents or webpages

Semantic HTML is the use of HTML markup to reinforce the semantics, or meaning, of the information in web pages and web applications rather than merely to define its presentation or look. Semantic HTML is processed by traditional web browsers as well as by many other user agents. CSS is used to suggest its presentation to human users.

<span class="mw-page-title-main">Metadata</span> Data about data

Metadata is "data that provides information about other data", but not the content of the data itself, such as the text of a message or the image itself. There are many distinct types of metadata, including:

XFrames is an XML format for combining and organizing web based documents together on a single webpage through the use of frames. Similarly to HTML Frames, XFrames can be made useful through its power to create a content frame that is scrollable while other frames - such as sidebar menus, the header and footer remain in place on the page. XFrames will be particularly useful to web developers who will be able to modify a single document and have that modification appear on all pages that contain the document within a frame.

Microdata is a WHATWG HTML specification used to nest metadata within existing content on web pages. Search engines, web crawlers, and browsers can extract and process Microdata from a web page and use it to provide a richer browsing experience for users. Search engines benefit greatly from direct access to Microdata because it allows them to understand the information on web pages and provide more relevant results to users. Microdata uses a supporting vocabulary to describe an item and name-value pairs to assign values to its properties. Microdata is an attempt to provide a simpler way of annotating HTML elements with machine-readable tags than the similar approaches of using RDFa and microformats.

XHTML+RDFa is an extended version of the XHTML markup language for supporting RDF through a collection of attributes and processing rules in the form of well-formed XML documents. XHTML+RDFa is one of the techniques used to develop Semantic Web content by embedding rich semantic markup. Version 1.1 of the language is a superset of XHTML 1.1, integrating the attributes according to RDFa Core 1.1. In other words, it is an RDFa support through XHTML Modularization.

A canonical link element is an HTML element that helps webmasters prevent duplicate content issues in search engine optimization by specifying the "canonical" or "preferred" version of a web page. It is described in RFC 6596, which went live in April 2012.

References

  1. ↑ "HTML meta tag". www.w3schools.com. Retrieved 2021-04-22.
  2. ↑ "Meta tags that Google understands – Search Console Help". support.google.com. Retrieved 2018-10-15.
  3. ↑ Statistic (June 4, 1997), META attributes by count, Vancouver Webpages, retrieved June 3, 2007
  4. ↑ "In 2007, 37 leaders in search engine optimisation concluded that having keywords in the keywords attribute is little to none." Sanger.nu blog, September 9 2008, Retrieved August 2 2011 Archived 2009-02-21 at the Wayback Machine
  5. ↑ "Google does not use the keywords meta tag in web ranking" Google Webmaster Central Blog, September 21, 2009, Retrieved September 21, 2009
  6. ↑ Yahoo! FAQs, How do I improve the ranking of my web site in the search results?, Yahoo.com, retrieved November 12, 2008
  7. ↑ "Yahoo Drops The Meta Keywords Tag Also" SEO Roundtable, October 8, 2009, Retrieved April 22, 2011
  8. 1 2 "Yahoo's Senior Director of Search Got It Wrong, Yahoo Uses Meta Keywords Still" SEO Roundtable, October 16, 2009, Retrieved April 22, 2011
  9. ↑ "A newly hatched way to tag your news articles". Google News Blog. Retrieved 2018-10-15.
  10. ↑ "Meta news keywords still works ?", Google Publisher Center Community, retrieved March 6, 2020
  11. ↑ "On-Page Ranking Factors – SEO Best Practices". Moz. 2017-04-24. Retrieved 2017-04-25.
  12. ↑ Vanessa Fox, Using the robots meta tag, Official Google Webmaster Central Blog, 3/05/2007
  13. ↑ Danny Sullivan (March 5, 2007),Meta Robots Tag 101: Blocking Spiders, Cached Pages & More Archived 2008-09-27 at the Wayback Machine , SearchEngineLand.com, retrieved June 3, 2007
  14. ↑ If I block Google from crawling a page using a robots.txt disallow directive, will it disappear from search results?, developers.google.com, retrieved July 26, 2013
  15. ↑ Betsy Aoki (May 22, 2006), Opting Out of Open Directory Listings for Webmasters, Live Search Blog, retrieved June 3, 2007
  16. ↑ Vanessa Fox (July 13, 2006), More control over page snippets, Inside Google Sitemaps, retrieved June 3, 2007
  17. ↑ Yahoo! Search (October 24, 2006), Yahoo! Search Weather Update and Support for 'NOODP', Yahoo! Search Blog, retrieved June 3, 2007
  18. ↑ Better Snippets for your Users
  19. ↑ Yahoo! Search (February 28, 2007), Yahoo! Search Support for 'NOYDIR' Meta Tags and Weather Update Archived 2008-11-06 at the Wayback Machine , Yahoo! Search Blog, retrieved June 3, 2007
  20. ↑ Greta de Groat (2002). "Perspectives on the Web and Google: Monika Henzinger, Director of Research, Google", Journal of Internet Cataloging, Vol. 5(1), pp. 17–28, 2002.
  21. ↑ "Meta Tags 2". Swiftype. 2014-03-10. Retrieved 2017-11-08.
  22. 1 2 "Welcome to the Virtual Mall!". www.w3.org. Retrieved 2018-10-15.
  23. ↑ Accessibility.blockautorefresh mozillaZine, archived June 2, 2009 from the original
  24. ↑ W3C Recommendation (May 5, 1999), Web Content Accessibility Guidelines 1.0 – Guideline 7. W3.org, retrieved September 28, 2007
  25. ↑ W3C Recommendation (December 24, 1999), HTML 4.01 Specification. W3.org, retrieved July 24, 2012
  26. ↑ Stack Overflow, 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.
  27. 1 2 "The global structure of an HTML document". www.w3.org. Retrieved 2018-10-15.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.