Anchors must only be used as links with valid URLs or URL fragments

Rule ID: href-no-hash
Ruleset: axe-core 4.0
User Impact: Serious
Guidelines: Deque Best Practice

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Compliance Data & Impact

User Impact

Serious
▼
Minor
Critical

Disabilities Affected

  • Blind
  • Deafblind
  • Mobility

Standard(s)

  • Deque Best Practice

    How to Fix the Problem

    Provide a valid link destination in the href attribute to ensure that links function properly even with JavaScript turned off. In particular, you should avoid href="" or href="#". The "#" symbol is used as a "fragment identifier separator", which means its intended purpose within the href attribute is to precede a string of text which identifies a fragment within the page (a named anchor or an ID on the page). The use of "#" as the hypertext reference essentially means that the anchor points to nothing. In some browsers this may "point" to the entire document or to the top of the page, and this will cause an unexpected shift in focus.

    Examples

    Link href Recommendations
    Recommended Not Recommended

    Placing a link to another page in the href value:

    <a href="index.html">
  Home
</a>

    Placing a link to an internal destination on the same page in the href value: 

    <a href="rules/axe/html#annual">
  Annual Reports
</a>

    Placing a valid link in the href attribute, plus a JavaScript function: 

    <a href="http://www.deque.com" 
onclick="window.open(this.href); 
return false;">
  Annual Reports
</a>

    Leaving off the href attribute:

    <a 
onclick="window.location.href=index.html">
  Home
</a>

    Placing nothing in the href attribute:

    <a href="" 
onclick="window.location.href=index.html">
  Home
</a>

    Placing "#" in the href attribute:

    <a href="class/html-css1/navigation/links#" 
onclick="window.location.href=index.html">
  Home
</a>

    Placing a JavaScript function in the href attribute:

    <a href="javascript:void(0)" 
onclick="myFunc();">
  Annual Reports
</a>

    Why it Matters

    Inaccessible link elements pose barriers to accessibility, as they are a fundamental component of a website.

    Users who rely exclusively on a keyboard (and no mouse) to navigate a webpage can only click on links that can receive programmatic focus. If a link cannot receive programmatic focus, it will be inaccessible to these users.

    Like sighted users, screen reader users need to know where a link is pointing. Inner link text provides this information, though it won't be useful if a screen reader can't access it.

    Keyboard users — such as blind screen reader users or people who cannot use a mouse due to tremors in their hands — can activate only the links and form elements that can receive programmatic focus. They cannot activate anything that cannot receive a programmatic focus. If any events are activated exclusively by the other types of focus, for example onmouseover events that depend on the mouse hover focus — those events will be inaccessible to keyboard users. By default, only links and form elements receive keyboard focus. Other elements can be modified to receive focus by adding tabindex="0".

    Rule Description

    Anchor links must be used with valid URLs or URL fragments so that they are discernible by a screen reader.

    The Algorithm (in simple terms)

    Ensures that every anchor link is used as a link with a valid URL or URL fragment.

    Resources

    Deque University Course Pages (subscription required)

    Contribute to axe-core on GitHub

    Other Resources

    You may also want to check out these other resources.

    Refer to the complete list of axe 4.0 rules.

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