<a>: The Anchor element

The <a> HTML element (or anchor element), with its href attribute, creates a hyperlink to web pages, files, email addresses, locations in the same page, or anything else a URL can address.

Content within each <a> should indicate the link's destination. If the href attribute is present, pressing the enter key while focused on the <a> element will activate it.

This element's attributes include the global attributes.

download

Causes the browser to treat the linked URL as a download. Can be used with or without a value:

• Without a value, the browser will suggest a filename/extension, generated from various sources:
  • The Content-Disposition HTTP header
  • The final segment in the URL path
  • The media type (from the Content-Type header, the start of a data: URL, or Blob.type for a blob: URL)
• Defining a value suggests it as the filename. / and \ characters are converted to underscores (_). Filesystems may forbid other characters in filenames, so browsers will adjust the suggested name if necessary.

Note:

• download only works for same-origin URLs, or the blob: and data: schemes.
• How browsers treat downloads varies by browser, user settings, and other factors. The user may be prompted before a download starts, or the file may be saved automatically, or it may open automatically, either in an external application or in the browser itself.
• If the Content-Disposition header has different information from the download attribute, resulting behavior may differ:
  • If the header specifies a filename, it takes priority over a filename specified in the download attribute.
  • If the header specifies a disposition of inline, Chrome and Firefox prioritize the attribute and treat it as a download. Old Firefox versions (before 82) prioritize the header and will display the content inline.

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:

• Sections of a page with fragment URLs
• Pieces of media files with media fragments
• Telephone numbers with tel: URLs
• Email addresses with mailto: URLs
• While web browsers may not support other URL schemes, web sites can with registerProtocolHandler()

hreflang

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

ping

A space-separated list of URLs. When the link is followed, the browser will send POST requests with the body PING to the URLs. Typically for tracking.

referrerpolicy

How much of the referrer to send when following the link.

• no-referrer: The Referer header will not be sent.
• no-referrer-when-downgrade: The Referer header will not be sent to origins without TLS (HTTPS).
• origin: The sent referrer will be limited to the origin of the referring page: its scheme, host, and port.
• origin-when-cross-origin: The referrer sent to other origins will be limited to the scheme, the host, and the port. Navigations on the same origin will still include the path.
• same-origin: A referrer will be sent for same origin, but cross-origin requests will contain no referrer information.
• strict-origin: Only send the origin of the document as the referrer when the protocol security level stays the same (HTTPS→HTTPS), but don't send it to a less secure destination (HTTPS→HTTP).
• strict-origin-when-cross-origin (default): Send a full URL when performing a same-origin request, only send the origin when the protocol security level stays the same (HTTPS→HTTPS), and send no header to a less secure destination (HTTPS→HTTP).
• unsafe-url: The referrer will include the origin and the path (but not the fragment, password, or username). This value is unsafe, because it leaks origins and paths from TLS-protected resources to insecure origins.

rel

The relationship of the linked URL as space-separated link types.

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 (the "highest" context that's an ancestor of the current one). If no ancestors, behaves as _self.

Note: Setting target="_blank" on <a> elements implicitly provides the same rel behavior as setting rel="noopener" which does not set window.opener. See browser compatibility for support status.

type

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

charset

Hinted at the character encoding of the linked URL.

Note: This attribute is deprecated and should not be used by authors. Use the HTTP Content-Type header on the linked URL.

coords

Used with the shape attribute. A comma-separated list of coordinates.

name

Was required to define a possible target location in a page. In HTML 4.01, id and name could both be used on <a>, as long as they had identical values.

Note: Use the global attribute id instead.

rev

Specified a reverse link; the opposite of the rel attribute. Deprecated for being very confusing.

shape

The shape of the hyperlink's region in an image map.

Note: Use the <area> element for image maps instead.

HTML

<a href="https://www.mozilla.com">
  Mozilla
</a>

Result

HTML

<a href="//example.com">Scheme-relative URL</a>
<a href="/en-US/docs/Web/HTML">Origin-relative URL</a>
<a href="./p">Directory-relative URL</a>

a { display: block; margin-bottom: 0.5em }

Result

To create links that open in the user's email program to let them send a new message, use the mailto: scheme:

<a href="mailto:nowhere@mozilla.org">Send email to nowhere</a>

For details about mailto: URLs, such as including a subject or body, see Email links or RFC 6068.

<a href="tel:+49.157.0156">+49 157 0156</a>
<a href="tel:+1(555)5309">(555) 5309</a>

tel: link behavior varies with device capabilities:

• Cellular devices autodial the number.
• Most operating systems have programs that can make calls, like Skype or FaceTime.
• Websites can make phone calls with registerProtocolHandler, such as web.skype.com.
• Other behaviors include saving the number to contacts, or sending the number to another device.

See RFC 3966 for syntax, additional features, and other details about the tel: URL scheme.

To save a <canvas> element's contents as an image, you can create a link with a download attribute and the canvas data as a data: URL:

Example painting app with save link

HTML

<p>Paint by holding down the mouse button and moving it.
  <a href="" download="my_painting.png">Download my painting</a>
</p>

<canvas width="300" height="300"></canvas>

CSS

html {
  font-family: sans-serif;
}
canvas {
  background: #fff;
  border: 1px dashed;
}
a {
  display: inline-block;
  background: #69c;
  color: #fff;
  padding: 5px 10px;
}

JavaScript

var canvas = document.querySelector('canvas'),
    c = canvas.getContext('2d');
c.fillStyle = 'hotpink';

function draw(x, y) {
  if (isDrawing) {
    c.beginPath();
    c.arc(x, y, 10, 0, Math.PI*2);
    c.closePath();
    c.fill();
  }
}

canvas.addEventListener('mousemove', event =>
  draw(event.offsetX, event.offsetY)
);
canvas.addEventListener('mousedown', () => isDrawing = true);
canvas.addEventListener('mouseup', () => isDrawing = false);

document.querySelector('a').addEventListener('click', event =>
  event.target.href = canvas.toDataURL()
);

Result

<a> elements can have consequences for users' security and privacy. See Referer header: privacy and security concerns for information.

Using target="_blank" without rel="noreferrer" and rel="noopener" makes the website vulnerable to window.opener API exploitation attacks (vulnerability description), although note that, in newer browser versions setting target="_blank" implicitly provides the same protection as setting rel="noopener". See browser compatibility for details.

The content inside a link should indicate where the link goes, even out of context.

Inaccessible, weak link text

A sadly common mistake is to only link the words "click here" or "here":

<p>
  Learn more about our products <a href="/products">here</a>.
</p>

Strong link text

Luckily, this is an easy fix, and it's actually shorter than the inaccessible version!

<p>
  Learn more <a href="/products">about our products</a>.
</p>

Assistive software has shortcuts to list all links on a page. However, strong link text benefits all users — the "list all links" shortcut emulates how sighted users quickly scan pages.

Anchor elements are often abused as fake buttons by setting their href to # or javascript:void(0) to prevent the page from refreshing, then listening for their click events .

These bogus href values cause unexpected behavior when copying/dragging links, opening links in a new tab/window, bookmarking, or when JavaScript is loading, errors, or is disabled. They also convey incorrect semantics to assistive technologies, like screen readers.

Use a <button> instead. In general, you should only use a hyperlink for navigation to a real URL.

Links that open in a new tab/window via target="_blank", or links that point to a download file should indicate what will happen when the link is followed.

People experiencing low vision conditions, navigating with the aid of screen reading technology, or with cognitive concerns may be confused when a new tab, window, or application opens unexpectedly. Older screen-reading software may not even announce the behavior.

Link that opens a new tab/window

<a target="_blank" href="https://www.wikipedia.org">
  Wikipedia (opens in new tab)
</a>

Link to a non-HTML resource

<a href="2017-annual-report.ppt">
  2017 Annual Report (PowerPoint)
</a>

If an icon is used to signify link behavior, make sure it has alt text:

<a  target="_blank" href="https://www.wikipedia.org">
  Wikipedia
  <img alt="(opens in new tab)" src="newtab.svg">
</a>

<a href="2017-annual-report.ppt">
  2017 Annual Report
  <img alt="(PowerPoint file)" src="ppt-icon.svg">
</a>

• WebAIM: Links and Hypertext - Hypertext Links
• MDN / Understanding WCAG, Guideline 3.2
• G200: Opening new windows and tabs from a link only when necessary
• G201: Giving users advanced warning when opening a new window

A skip link is a link placed as early as possible in <body> content that points to the beginning of the page's main content. Usually, CSS hides a skip link offscreen until focused.

<body>
  <a href="#content" class="skip-link">Skip to main content</a>

  <header>
    …
  </header>

  <main id="content"> </main> <!-- The skip link jumps to here -->

</body>

.skip-link {
  position: absolute;
  top: -3em;
  background: #fff;
}
.skip-link:focus {
  top: 0;
}

Skip links let keyboard users bypass content repeated throughout multiple pages, such as header navigation.

Skip links are especially useful for people who navigate with the aid of assistive technology such as switch control, voice command, or mouth sticks/head wands, where the act of moving through repetitive links can be laborious.

• WebAIM: "Skip Navigation" Links
• How-to: Use Skip Navigation links
• MDN / Understanding WCAG, Guideline 2.4 explanations
• Understanding Success Criterion 2.4.1

Size

Interactive elements, like links, should provide an area large enough that it is easy to activate them. This helps a variety of people, including those with motor control issues and those using imprecise inputs such as a touchscreen. A minimum size of 44×44 CSS pixels is recommended.

Text-only links in prose content are exempt from this requirement, but it's still a good idea to make sure enough text is hyperlinked to be easily activated.

• Understanding Success Criterion 2.5.5: Target Size
• Target Size and 2.5.5
• Quick test: Large touch targets

Proximity

Interactive elements, like links, placed in close visual proximity should have space separating them. Spacing helps people with motor control issues, who may otherwise accidentally activate the wrong interactive content.

Spacing may be created using CSS properties like margin.

• Hand tremors and the giant-button-problem

• <link> is similar to <a>, but for metadata hyperlinks that are invisible to users.
• :link is a CSS pseudo-class that will match <a> elements with valid href attributes.