mozilla
Your Search Results

    <meta>

    Summary

    The HTML <meta> Element represents any metadata information that cannot be represented by one of the other meta-related elements (<base>, <link>, <script>, <style> or <title>). According to the attributes set, the kind of metadata can be one of the following:

    • if the name is set, a document-level metadata, applying to the whole page;
    • if the http-equiv is set, a pragma directive, i.e. information normally given from the webserver on how the webpage should be served;
    • if the charset is set, a charset declaration, i.e. the charset used for the serialized-form of the webpage; HTML5
    • if the itemprop is set, a user-defined metadata, transparent for the user-agent as the semantics of the metadata is user-specific. Living Standard Unimplemented
    • Content categoriesMetadata content. If the itemprop attribute is present: flow content, phrasing content.
    • Permitted content None, it is an empty element.
    • Tag omission As it is a void element, the start tag must be present and the end tag must not be present.
    • Permitted parent elements<meta charset>, <meta http-equiv>: a <head> element. If the http-equiv is not an encoding declaration, it can also be inside a <noscript> element, itself inside a <head> element.
      <meta name>: any element that accepts metadata content.
      <meta itemprop>: any element that accepts metadata content or parsing content.
    • DOM interface HTMLMetaElement

    Attributes

    This element includes the global attributes.

    Note that the global name has a specific semantic in the <meta> element and that the itemprop must not be set when one of the name, http-equiv or charset is already used.

    charset HTML5
    This attribute declares the character encoding used of the page. It can be locally overridden using the lang attribute on any element. This attribute is a literal string and must be one of the preferred MIME name for a character encoding as defined by the IANA. Though the standard doesn't request a specific character encoding, it gives some recommendations:
    • Authors are encouraged to use UTF-8.
    • Authors should not use ASCII-incompatible encodings (i.e. those that don't map the 8-bit code points 0x20 to 0x7E to the Unicode 0x0020 to 0x007E code points) as these represent a security risk: browsers not supporting them may interpret benign content as HTML Elements. This is the case of at least the following charsets: JIS_C6226-1983, JIS_X0212-1990, HZ-GB-2312, JOHAB, the ISO-2022 family, and the EBCDIC family.
    • Authors must not use CESU-8, UTF-7, BOCU-1 and SCSU, also falling in that category and not intended to be used on the web. Cross-scripting attacks with some of these encodings have been documented.
    • Authors should not use UTF-32 because not all HTML5 encoding algorithms can distinguish it from UTF-16.
    Notes:
    • The declared character set must match the one of the page. There is no valid reason to declare an inaccurate character set.
    • This <meta> element must be inside the <head> element and within the 512 first bytes of the page, as some browsers only look at these first bytes before choosing a character set for the page.
    • This <meta> element is only a part of the algorithm to determine the character set of a page that browsers apply. The HTTP Content-Type header and any BOM elements have precedence over this element.
    • It is good practice, and strongly recommended, to define the character set using this attribute. If no character set is defined for a page, several cross-scripting techniques may be able to harm the page user, such as the UTF-7 fallback cross-scripting technique. Always setting this meta will protect against these risks.
    • This <meta> element is a synonym for the pre-HTML5 <meta http-equiv="Content-Type" content="text/html; charset=IANAcharset"> where IANAcharset corresponds of the value of the equivalent charset attribute. This syntax is still allowed, although obsolete and no more recommended.
    content
    This attribute gives the value associated with the http-equiv or name attribute, depending of the context.
    http-equiv
    This enumerated attribute defines the pragma that can alter servers and user-agents behavior. The value of the pragma is defined using the content and can be one of the following:
    content-language
    This pragma defines the default language of the page.
    Usage note: do not use this pragma as it is obsolete. Use the global lang attribute on the <body> element instead.
    content-type
    This attribute defines the MIME type of the document, eventually followed by its character set. It follows the same syntax as the HTTP content-type entity-header field, but as it is inside an HTML Element, most values are not possible. Therefore the valid syntax for its content is the literal string 'text/html' eventually followed by a character set with the following syntax:'; charset=IANAcharset' where IANAcharset is the preferred MIME name for a character set as defined by the IANA.
    Usage note:
    • Do not use this pragma as it is obsolete. Use the charset attribute on the <meta> element instead.
    • As the <meta> may not be used to change the type of a document in an XHTML document, or in an HTML5 document following the XHTML syntax, never set MIME type to an XHTML MIME type that way. It would be incorrect.
    • Only an HTML document can use the content-type, so most of it is redundant: that's why it has been obsoleted and replaced by the charset attribute.
    default-style
    This pragma specifies the preferred stylesheet to be used on the page. The content attribute must contain the id of a <link> element whose href attribute links to a CSS stylesheet, or the id of a <style> element which contains a CSS stylesheet.
    refresh
    This pragma specifies:
    • the number of seconds until the page should be reloaded, if the content attribute contains only a positive integer number;
    • the number of seconds until the page should be redirected to another, if the content attribute contains a positive integer number followed by the string ';url=' and a valid URL.
    set-cookie
    This pragma defines a cookie for the page. Its content must follows the syntax defines in the IETF HTTP Cookie Specification.
    Note: Do not use this pragma as it is obsolete. Use the HTTP header set-cookie instead.
    name
    This attribute defines the name of a document-level metadata. It should not be set if one of the attributes itemprop, http-equiv or charset is also set.
    This document-level metadata name is associated with a value, contained by the content attribute. The possible values for the name element are, with their associated value, stored via the content attribute:
    • application-name, defining the name of the web application running in the webpage;
      Note:
      • Browsers may use this to identify the application. It is different from the <title> element, which usually consist of the application name but may also contain specific information like the document name or a status;
      • Simple webpages shouldn't define the application-name meta.
    • author, defining, in a free format, the name of the author of the document;
    • description, containing a short and accurate summary of the content of the page. Several browsers, among them Firefox and Opera, use this meta as the default description of the page when bookmarked;
    • generator, containing, in a free format, the identifier to the software that generated the page;
    • keywords, containing, as strings separated by commas, relevant words associated with the content of the page.

    The attribute may also have a value taken from the extended list defined on WHATWG Wiki MetaExtensions page. Although none has been formally accepted yet, a few commonly used names are among the proposals:

    • creator, defining, in a free format, the name of the creator of the document. Note that it can be the name of the institution. If there are more than one, several <meta> elements should be used;
    • googlebot, which is a synonym of robots, but is only followed by Googlebot, the indexing crawler for Google;
    • publisher, defining, in a free format, the name of the publisher of the document. Note that it can be the name of the institution;
    • robots, defining the behavior that cooperative crawlers should have with the page. It is a comma-separated list of values taken in the following list:
      Values for the content of <meta name="robots">
      Value Description Used by
      index Allows the robot to index the page All
      noindex Prevents the robot from indexing the page All
      follow Allows the robot to follow the links on the page All
      nofollow Prevents the robot from following the links on the page All
      noodp Prevents the usage of the Open Directory Project description, if any, as the description of the page in the search engine results page

      Google, Yahoo, Bing
      noarchive Prevents the search engine from caching the content of the page Google, Yahoo
      nosnippet Prevents the display of any description of the page in the search engine results page Google
      noimageindex Prevents this page from appearing as the referring page of an indexed image Google
      noydir Prevents the usage of the Yahoo Directory description, if any, as the description of the page in the search engine results page Yahoo
      nocache Synonym of noarchive Bing
      Notes:
      • Only cooperative robots will follow the rules defined by the robots name. Do not expect to keep e-mail harvesters at bay with this.
      • The robot still needs to access the page in order to read the meta value. If you want to keep them at bay, for example to prevent bandwidth consumption, use a robots.txt file instead (or in complement).
      • If you want to remove the page of an index, changing the meta to noindex will work, but only when the robot visit the page again. Be sure not to prevent such visits, via the robots.txt file for example. Some search engines have developers tools, allowing a quick removal of some page.
      • Some possible values are mutually exclusive, like using index and noindex, or follow and nofollow, at the same time. In these cases the behavior of the robot is undefined, and may vary from one to the other. So avoid these cases.
      • Some search engine crawler robots, like those of Google, Yahoo Search or Bing, support the same values on an HTTP directive, X-Robot-Tags: this allows them to use these pragma on non-HTML documents, like images.
    • slurp, which is a synonym of robots, but is only followed by Slurp, the indexing crawler for Yahoo Search;

    Finally a few names are in common use, though not in progress of being standardized:

    • viewport, which gives hints about the size of the initial size of the viewport. This pragma is used by several mobile devices only.
      Values for the content of <meta name="viewport">
      Value Possible values Description
      width a positive integer number or the literal device-width defines the width, in pixels, of the viewport
      height a positive integer number of the literal device-height defines the height, in pixels, of the viewport
      initial-scale a positive number between 0.0 and 10.0 defines the ratio between the device width (device-width in portrait mode or device-height in landscape mode) and the viewport size.
      maximum-scale a positive number between 0.0 and 10.0 defines the maximum value of the zoom; it must be greater or equal to the minimum-scale or the behavior is indeterminate.
      minimum-scale a positive number between 0.0 and 10.0 defines the minimum value of the zoom; it must be smaller or equal to the maximum-scale or the behavior is indeterminate.
      user-scalable a boolean value (yes or no) If set to no, the user is not able to zoom in the webpage. Default value is yes.
      Specification Status Comment
      CSS Device Adaptation
      The definition of '<meta name="viewport">' in that specification.      		 Working Draft Non-normatively describes the Viewport META element
      See also: @viewport
      Notes:
      • Though not standardized, this attribute is used by different mobile browsers like Safari Mobile, Firefox for Mobile or Opera Mobile.
      • The default values may change from one device, and browser, to another.
      • To learn about this pragma in Firefox for Mobile, see this article.
    scheme
    This attribute defines the scheme in which the metadata is described. A scheme is a context leading to the correct interpretations of the content value, like a format.
    Notes: Do not use this attribute as it is obsolete. There is no replacement for it as there was no real usage for it. Omit it altogether.

    Examples

    <!-- Defining the charset in HTML4 -->
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">

<!-- In HTML5 -->
<meta charset="utf-8">

<!-- Redirect page after 3 seconds -->
<meta http-equiv="refresh" content="3;url=http://www.mozilla.org/">

    Specifications

    Specification Status Comment
    WHATWG HTML Living Standard
    The definition of '<meta>' in that specification.    		 Living Standard  
    HTML5
    The definition of '<meta>' in that specification.    		 Candidate Recommendation  
    HTML 4.01 Specification
    The definition of '<meta>' in that specification.    		 Recommendation  

    Browser compatibility

    Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
    Basic support (Yes) 1.0 (1.7 or earlier) (Yes) (Yes) (Yes)
    Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
    Basic support (Yes) 1.0 (1.0) (Yes) (Yes) (Yes)

    See also

    Document Tags and Contributors

    Tags: 
    Contributors to this page: alexjohnj, lmorchard, JuliaKM, wongkit, mapguymike, KyliRouge, medicdude, fscholz, meowris, brendangibson, cvrebert, nimbupani, rvighne, Tantek, systemovich, Sheppy, tregagnon, ludder, materthron, osdm, jmlaurelli, teoli, McGurk, FreakCERS, AndreZSanchez, kscarfone, JamieT, ethertank, justleroy, afzaal_ahmad_zeeshan, Ms2ger, knuton
    Last updated by: wongkit,