<meta>: The Document-level Metadata element - HTML: HyperText Markup Language 编辑

The HTML <meta> element represents metadata that cannot be represented by other HTML meta-related elements, like <base>, <link>, <script>, <style> or <title>.

The type of metadata provided by the meta element can be one of the following:

• If the name attribute is set, the meta element provides document-level metadata, applying to the whole page.
• If the http-equiv attribute is set, the meta element is a pragma directive, providing information equivalent to what can be given by a similarly-named HTTP header.
• If the charset attribute is set, the meta element is a charset declaration, giving the character encoding in which the document is encoded.
• If the itemprop attribute is set, the meta element provides user-defined metadata.

Attributes

This element includes the global attributes.

Note: the attribute name has a specific meaning for the <meta> element, and the itemprop attribute must not be set on the same <meta> element that has any existing name, http-equiv or charset attributes.

charset

This attribute declares the document's character encoding. If the attribute is present, its value must be an ASCII case-insensitive match for the string "utf-8", because UTF-8 is the only valid encoding for HTML5 documents. meta elements which declare a character encoding must be located entirely within the first 1024 bytes of the document.

content

This attribute contains the value for the http-equiv or name attribute, depending on which is used.

http-equiv

Defines a pragma directive. The attribute is named http-equiv(alent) because all the allowed values are names of particular HTTP headers:

• content-security-policy

  Allows page authors to define a content policy for the current page. Content policies mostly specify allowed server origins and script endpoints which help guard against cross-site scripting attacks.

• content-type

  Declares the MIME type and character encoding of the document. If specified, the content attribute must have the value "text/html; charset=utf-8". This is equivalent to a meta element with the charset attribute specified, and carries the same restriction on placement within the document. Note: Can only be used in documents served with a text/html — not in documents served with an XML MIME type.

• default-style

  Sets the name of the default CSS style sheet set.

• x-ua-compatible

  If specified, the content attribute must have the value "IE=edge". User agents are required to ignore this pragma.

• refresh This instruction specifies:
  • The number of seconds until the page should be reloaded - only if the content attribute contains a positive integer.
  • The number of seconds until the page should redirect to another - only if the content attribute contains a positive integer followed by the string ';url=', and a valid URL.

  Accessibility concerns

  Pages set with a refresh value run the risk of having the time interval being too short. People navigating with the aid of assistive technology such as a screen reader may be unable to read through and understand the page's content before being automatically redirected. The abrupt, unannounced updating of the page content may also be disorienting for people experiencing low vision conditions.
  • MDN Understanding WCAG, Guideline 2.1 explanations
  • MDN Understanding WCAG, Guideline 3.1 explanations
  • Understanding Success Criterion 2.2.1 | W3C Understanding WCAG 2.0
  • Understanding Success Criterion 2.2.4 | W3C Understanding WCAG 2.0
  • Understanding Success Criterion 3.2.5 | W3C Understanding WCAG 2.0

name

The name and content attributes can be used together to provide document metadata in terms of name-value pairs, with the name attribute giving the metadata name, and the content attribute giving the value.

See standard metadata names for details about the set of standard metadata names defined in the HTML specification.

Examples

<meta charset="utf-8">

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

Specifications

Browser compatibility

BCD tables only load in the browser