<a>

Attributes

This element's attributes include the global MathML attributes as well as the following attributes:

href

The URL that the hyperlink points to. Links are not restricted to HTTP-based URLs — they can use any URL scheme supported by browsers:

Telephone numbers with tel: URLs
Email addresses with mailto: URLs
SMS text messages with sms: URLs
Executable code with javascript: URLs
While web browsers may not support other URL schemes, websites can with registerProtocolHandler()

Moreover other URL features can locate specific parts of the resource, including:

Sections of a page with document fragments
Specific text portions with text fragments
Pieces of media files with media fragments

hreflang

Hints at the human language of the linked URL. No built-in functionality. Allowed values are the same as the global lang attribute.

target

Where to display the linked URL, as the name for a browsing context (a tab, window, or <iframe>). The following keywords have special meanings for where to load the URL:

_self: The current browsing context. (Default)
_blank: Usually a new tab, but users can configure browsers to open a new window instead.
_parent: The parent browsing context of the current one. If no parent, behaves as _self.
_top: The topmost browsing context. To be specific, this means the "highest" context that's an ancestor of the current one. If no ancestors, behaves as _self.

type

Hints at the linked URL's format with a MIME type. No built-in functionality.

Examples

Basic usage

This example marks up the Gamma function in MathML. It includes several nested MathML <a> elements to link individual parts of the formula to their respective sections on the Wiki page.

MathML

html

<math display="block" xmlns="http://www.w3.org/1998/Math/MathML"
  ><semantics
    ><mrow
      ><a href="https://en.wikipedia.org/wiki/Gamma_function"
        ><mrow
          ><mi mathvariant="normal">Γ</mi><mo stretchy="false">(</mo><mi>t</mi
          ><mo stretchy="false">)</mo></mrow
        ></a
      ><mo>=</mo
      ><a href="https://en.wikipedia.org/wiki/Gamma_function#Main_definition"
        ><mrow
          ><msubsup
            ><mo>∫</mo><mn>0</mn><mrow><mo>+</mo><mn>∞</mn></mrow></msubsup
          ><msup
            ><mi>x</mi><mrow><mi>t</mi><mo>−</mo><mn>1</mn></mrow></msup
          ><msup
            ><mi>e</mi><mrow><mo>−</mo><mi>x</mi></mrow></msup
          ><mi>d</mi><mi>x</mi></mrow
        ></a
      ><mo>=</mo
      ><a
        href="https://en.wikipedia.org/wiki/Gamma_function#Euler's_definition_as_an_infinite_product"
        ><mrow
          ><mfrac><mn>1</mn><mi>t</mi></mfrac
          ><munderover
            ><mo>∏</mo><mrow><mi>n</mi><mo>=</mo><mn>1</mn></mrow
            ><mn>∞</mn></munderover
          ><mfrac
            ><msup
              ><mrow
                ><mo>(</mo
                ><mrow
                  ><mn>1</mn><mo>+</mo><mfrac><mn>1</mn><mi>n</mi></mfrac></mrow
                ><mo>)</mo></mrow
              ><mi>t</mi></msup
            ><mrow
              ><mn>1</mn><mo>+</mo><mfrac><mi>t</mi><mi>n</mi></mfrac></mrow
            ></mfrac
          ></mrow
        ></a
      ><a href="https://en.wikipedia.org/wiki/Asymptotic_analysis#Definition"
        ><mo>∼</mo></a
      ><a href="https://en.wikipedia.org/wiki/Gamma_function#Stirling's_formula"
        ><mrow
          ><msqrt
            ><mfrac
              ><mrow><mn>2</mn><mi>π</mi></mrow
              ><mi>t</mi></mfrac
            ></msqrt
          ><msup
            ><mrow
              ><mo>(</mo><mfrac><mi>t</mi><mi>e</mi></mfrac
              ><mo>)</mo></mrow
            ><mi>t</mi></msup
          ></mrow
        ></a
      ></mrow
    ></semantics
  ></math
>