Warnings

Invalid nesting in a list

Description

The only child allowed in <ul> and <ol> is <li> - and the converse is also true.

References

Selector

ul > :not(li),
ol > :not(li),
:not(ul, ol) > li

Test

I feel like I'm lost.

<ul>
  <p>I feel like I'm lost.</p>
</ul>

Invalid sibling in a definition list

Description

<dt> and <dd> should be direct adjacent siblings, and nothing else. Although multiple <dd> may follow a single <dt>.

References

Selector

dt + :not(dd),
:not(dt, dd) + dd

Test

I need a definition, don't you think?

<dl>
  <dt>I need a definition, don't you think?</dt>
  <li>I'm a list item.</li>
</dl>

Invalid nesting in a definition list

Description

<div>, <dt> and <dd> should be direct children of <dl>. Any other imbrication may be a crime somewhere.

References

Selector

:not(dl) > dt,
:not(dl) > dd,
dl > :not(dt, dd, div)

Test

I'm a list item.

<dl>
  <li>I'm a list item.</li>
</dl>

figcaption outside a figure

Description

<figcaption> doesn't make sense outside a <figure>.

References

Selector

:not(figure) > figcaption

Test

I'm captionning something, isn't it?

<figcaption>I'm captionning something, isn't it?</figcaption>

figure without the group ARIA role

Description

<figure> needs [role="group"] for accessibility reason.

References

Selector

figure:not([role="group"])

Test

<figure>
  <img src="/static/ffoodd.png" width="144" height="144" alt="Figcaption test"/>
  <figcaption>I'm a figcaption</figcaption>
</figure>

Invalid nesting

Description

Some nestings are forbidden, and do not have their own test case for now:

<main> contained in any of <nav>, <aside>, <footer>, <header> or <article>;
<address> containing any of <address>, <nav>, <aside>, <section>, <footer>, <header> or <article> — neither headings;
<option> and <optgroup> outside a <select>;
<legend> outside a <fieldset>;
<td> or <th> outside a <tr>;
direct children of a <table>;
<colgroup> containing anything else than <col>.

Maybe other invalid nestings to test. Stay tuned.

References

Selector

nav main,
aside main,
footer main,
header main,
article main,
:not(tr) > td,
:not(tr) > th,
colgroup *:not(col),
:not(colgroup) > col,
tr > :not(td, th),
optgroup > :not(option),
:not(select) > optgroup,
:not(fieldset) > legend,
select > :not(option, optgroup),
:not(select, optgroup) > option,
table > *:not(thead, tfoot, tbody, tr, colgroup, caption),
address h1,
address h2,
address h3,
address h4,
address h5,
address h6,
address nav,
address aside,
address header,
address footer,
address address,
address article,
address section

Test

I'm an legend. Am I?

<legend>I'm an legend. Am I?</legend>

Misplaced div

Description

Did you know that you shouldn't add a <div> inside any inline element? You could use a <span> instead.

References

https://github.com/Heydon/REVENGE.CSS/blob/master/revenge.css#L326

Selector

b div,
i div,
q div,
em div,
abbr div,
cite div,
code div,
span div,
small div,
label div,
strong div

Test

Hey ya!

<b><div>Hey ya!</div></b>

Misused sectioning tags

Description

<section>, <aside>, <article> are sectioning tags. They must not be used as wrappers!

References

Selector

aside > aside:first-child,
article > aside:first-child,
aside > article:first-child,
aside > section:first-child,
section > section:first-child,
article > section:first-child,
article > article:first-child

Test

<aside>
  <section>I'm wrapping, you know.</section>
</aside>

legend must be a fieldset's:first-child

Description

<legend> must be a <fieldset>'s:first-child. Always.

References

Selector

fieldset > *:not(legend):first-child,
fieldset > legend:not(:first-child)

Test

I'm not a legend.

<fieldset>
  <label>I'm not a legend.</label>
</fieldset>

summary must be a details's:first-child

Description

<summary> must be a <details>'s:first-child. Always.

References

Selector

details > *:not(summary):first-child,
details > summary:not(:first-child)

Test

I'm not a summary.

<details>
  <legend>I'm not a summary.</legend>
</details>

abbr should have a [title]

Description

Any abbreviation should give an explanation about its meaning, at least on its first occurrence.

References

Selector

abbr:not([title]),
abbr[title=" "],
abbr[title=""]

Test

Do you know about W3C?

<p>Do you know about <abbr>W3C</abbr>?</p>

[alt] can be empty but has to be checked

Description

An alternative has to be empty when image is decorative only. In any other case, [alt] must be defined. That should be double-checked.

References

Selector

img[alt=""],
area[alt=""],
input[type="image"][alt=""],
embed[type="image"][alt=""],
object[type="image"][alt=""]

Test

†

<img alt="" src="/static/ffoodd.png" width="144" height="144" /><span>†</span>

[alt] containing file name

Description

A file name in [alt] is probably wrongly automated… and would never ever help any user.

References

Selector

img[alt$=".pdf"],
area[alt$=".pdf"],
input[type="image"][alt$=".pdf"],
img[alt$=".doc"],
area[alt$=".doc"],
input[type="image"][alt$=".doc"],
img[alt$=".png"],
area[alt$=".png"],
input[type="image"][alt$=".png"],
img[alt$=".jpg"],
area[alt$=".jpg"],
input[type="image"][alt$=".jpg"],
img[alt$=".gif"],
area[alt$=".gif"],
input[type="image"][alt$=".gif"],
img[alt$=".mp3"],
area[alt$=".mp3"],
input[type="image"][alt$=".mp3"],
img[alt$=".mp4"],
area[alt$=".mp4"],
input[type="image"][alt$=".mp4"],
img[alt$=".mov"],
area[alt$=".mov"],
input[type="image"][alt$=".mov"],
img[alt$=".ogg"],
area[alt$=".ogg"],
input[type="image"][alt$=".ogg"],
img[alt$=".xls"],
area[alt$=".xls"],
input[type="image"][alt$=".xls"],
img[alt$=".txt"],
area[alt$=".txt"],
input[type="image"][alt$=".txt"],
img[alt$=".zip"],
area[alt$=".zip"],
input[type="image"][alt$=".zip"],
img[alt$=".rar"],
area[alt$=".rar"],
input[type="image"][alt$=".rar"],
img[alt$=".docx"],
area[alt$=".docx"],
input[type="image"][alt$=".docx"],
img[alt$=".webp"],
area[alt$=".webp"],
input[type="image"][alt$=".webp"],
img[alt$=".apng"],
area[alt$=".apng"],
input[type="image"][alt$=".apng"],
img[alt$=".svg"],
area[alt$=".svg"],
input[type="image"][alt$=".svg"],
img[alt$=".svgz"],
area[alt$=".svgz"],
input[type="image"][alt$=".svgz"],
embed[type="image"][alt$=".pdf"],
object[type="image"][alt$=".pdf"],
embed[type="image"][alt$=".doc"],
object[type="image"][alt$=".doc"],
embed[type="image"][alt$=".png"],
object[type="image"][alt$=".png"],
embed[type="image"][alt$=".jpg"],
object[type="image"][alt$=".jpg"],
embed[type="image"][alt$=".gif"],
object[type="image"][alt$=".gif"],
embed[type="image"][alt$=".mp3"],
object[type="image"][alt$=".mp3"],
embed[type="image"][alt$=".mp4"],
object[type="image"][alt$=".mp4"],
embed[type="image"][alt$=".mov"],
object[type="image"][alt$=".mov"],
embed[type="image"][alt$=".ogg"],
object[type="image"][alt$=".ogg"],
embed[type="image"][alt$=".xls"],
object[type="image"][alt$=".xls"],
embed[type="image"][alt$=".txt"],
object[type="image"][alt$=".txt"],
embed[type="image"][alt$=".zip"],
object[type="image"][alt$=".zip"],
embed[type="image"][alt$=".rar"],
object[type="image"][alt$=".rar"],
embed[type="image"][alt$=".docx"],
object[type="image"][alt$=".docx"],
embed[type="image"][alt$=".webp"],
object[type="image"][alt$=".webp"],
embed[type="image"][alt$=".apng"],
object[type="image"][alt$=".apng"],
embed[type="image"][alt$=".svg"],
object[type="image"][alt$=".svg"],
embed[type="image"][alt$=".svgz"],
object[type="image"][alt$=".svgz"]

Test

†

<img alt="/static/ffoodd.png" src="/static/ffoodd.png" width="144" height="144" /><span>†</span>

Decorative image shouldn't have an accessible name

Description

Any decorative image — with [aria-hidden="true"] or empty [alt] — shouldn't have any of those:

[title];
[aria-label];
[aria-labelledby];
[aria-describedby];
a <title> child;
or a <desc>.

This test currently can't check if any <title> nor <desc> child is present since <svg> is a replaced elements. See Edge cases and known issues on a11y.css' wiki.

References

Selector

img[alt=""][title],
img[alt=""][aria-label],
img[alt=""][aria-labelledby],
img[alt=""][aria-describedby],
area:not([href])[alt]:not([alt=""]),
area:not([href])[alt=""][title],
area:not([href])[alt=""][aria-label],
area:not([href])[alt=""][aria-labelledby],
area:not([href])[alt=""][aria-describedby],
svg[aria-hidden="true"][title],
svg[aria-hidden="true"][aria-label],
svg[aria-hidden="true"][aria-labelledby],
svg[aria-hidden="true"][aria-describedby],
canvas[aria-hidden="true"][title],
canvas[aria-hidden="true"][aria-label],
canvas[aria-hidden="true"][aria-labelledby],
canvas[aria-hidden="true"][aria-describedby],
embed[type="image"][aria-hidden="true"][title],
embed[type="image"][aria-hidden="true"][aria-label],
embed[type="image"][aria-hidden="true"][aria-labelledby],
embed[type="image"][aria-hidden="true"][aria-describedby],
object[type="image"][aria-hidden="true"][title],
object[type="image"][aria-hidden="true"][aria-label],
object[type="image"][aria-hidden="true"][aria-labelledby],
object[type="image"][aria-hidden="true"][aria-describedby],

Test

†

<svg width="12cm" height="4cm" viewBox="0 0 1200 400"
     xmlns="http://www.w3.org/2000/svg"
     aria-hidden="true" title="Decorative SVG, you punk!">
  <rect x="400" y="100" width="400" height="200"
        fill="forestgreen" stroke="darkgreen" stroke-width="10"  />
</svg><span>†</span>

[role=presentation] shouldn't be used on image

Description

Any decorative image should be marked up with [aria-hidden="true"] (or empty [alt] if <img>). [role=presentation] shall do the trick but at the time of writing, its support is too low compared to empty [alt] or [aria-hidden=true].

References

Selector

img[role="presentation"],
svg[role="presentation"],
area[role="presentation"],
embed[role="presentation"],
canvas[role="presentation"],
object[role="presentation"]

Test

†

<svg width="12cm" height="4cm" viewBox="0 0 1200 400"
     xmlns="http://www.w3.org/2000/svg"
     role="presentation">
  <rect x="400" y="100" width="400" height="200"
        fill="forestgreen" stroke="darkgreen" stroke-width="10"  />
</svg><span>†</span>

A role is needed for svg

Description

Any <svg> should either have [aria-hidden="true"] if decorative, or a [role="img"] if informative.

References

Selector

svg:not([aria-hidden="true"], [role="img"])

Test

†

<svg width="12cm" height="4cm" viewBox="0 0 1200 400"
     xmlns="http://www.w3.org/2000/svg"
     aria-label="Decorative SVG, you punk!">
  <rect x="400" y="100" width="400" height="200"
        fill="forestgreen" stroke="darkgreen" stroke-width="10"  />
</svg><span>†</span>

[autoplay] should probably not be used

Description

A time-based media like <audio> or <video> should not [autoplay], because it can be quite surprising for the user.

References

Selector

video[autoplay],
audio[autoplay]

Test

†

<video autoplay controls src=""></video><span>†</span>

[controls] would be helpful

Description

A time-based media like <audio> or <video> would be easier to use if [controls] are activated for the user.

References

Selector

video:not([controls]),
audio:not([controls])

Test

†

<video src=""></video><span>†</span>

Most of DOM nodes shouldn't be :empty

Description

Obviously void elements are empty, as well as <iframe> and <textarea> could be :empty. Any other :empty tag that is not hidden is probably useless, and should be deleted.

Please note that it's disabled for tags owning a source through [src]. It's pretty opinionated, but it's meant to avoid false positives on tags such as <video> or <audio> which may be empty if they have at least one source specified through [src].

Notes

This test only targets tags in <body>, since most of head's tags should be empty.
<button> and <a> are also excluded since button:empty and a:empty are both covered by their own error.

We could use the :blank pseudo-class, but at this time its support is very poor. We could also use the :-moz-only-whitespace pseudo-class, but support is limited to Firefox and thus could invalidate our selectors stack…

References

Selector

body *:empty:not([hidden], [aria-hidden], [src], button, a, iframe, textarea, area, base, br, col, command, embed, hr, img, input, keygen, link, meta, param, source, track, wbr, title)

Test

<p id="empty-node_code"></p>

A single line table may be used for layout

Description

A lonely <tr> can be a symptom of a table used for layout. Should be double checked!

References

Selector

table:not([role="presentation"]) > tr:only-child,
table:not([role="presentation"]) > tbody > tr:only-child

Test

I'm a caption :3
Oh boy…
I'm a poor lonesone table-roooow!

<table>
  <caption>I'm a caption :3</caption>
  <thead>
    <tr>
      <th scope="col">Oh boy…</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>I'm a poor lonesone table-roooow!</td>
    </tr>
  </tbody>
</table>

Nested tables

Description

There's no good reason to nest data tables: thus it probably means we're facing a layout table…

References

Selector

table table

Test

I'm a caption :3

Oh boy…

I'm a table-cell!

I'm a caption too!
Oh boy…
I'm a table-cell!
I'm a table-cell!

<table>
  <caption>I'm a caption :3</caption>
  <thead>
    <tr>
      <th scope="col">Oh boy…</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>I'm a table-cell!</td>
    </tr>
    <tr>
      <td>
        <table>
          <caption>I'm a caption too!</caption>
          <thead>
            <tr>
              <th scope="col">Oh boy…</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td>I'm a table-cell!</td>
            </tr>
            <tr>
              <td>I'm a table-cell!</td>
            </tr>
        </table>
      </td>
    </tr>
  </tbody>
</table>

Every data table must have a caption

Description

<caption> is needed for data <table>. And it must be the :first-child, by the way.

References

Selector

table:not([role="presentation"]) > caption:not(:first-child),
table:not([role="presentation"]) > *:first-child:not(caption)

Test

I'm a table without a caption!	I'm a table without a caption!
I'm a table without a caption!
I'm a table without a caption!

<table>
  <thead>
    <tr>
      <th id="th-one">I'm a table without a caption!</th>
      <th id="th-two">I'm a table without a caption!</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td colspan="2" headers="th-one th-two">I'm a table without a caption!</td>
    </tr>
    <tr>
      <td colspan="2" headers="th-one th-two">I'm a table without a caption!</td>
    </tr>
  </tbody>
</table>

Invalid table structure

Description

<thead>, <tfoot> and <tbody> must be in this order.

References

Selector

table > tfoot ~ thead,
table > tbody ~ tfoot,
table > tbody ~ thead,
table > tfoot ~ colgroup,
table > tbody ~ colgroup,
table > tbody ~ colgroup

Test

I'm a caption
Where's my foot?
I'm a table with tfoot done wrong.	I'm a table with tfoot done wrong.
I'm a table with tfoot done wrong.	I'm a table with tfoot done wrong.
I'm a table with tfoot done wrong.	I'm a table with tfoot done wrong.

<table>
  <caption>I'm a caption</caption>
  <thead>
    <tr>
      <th scope="col">Where's my foot?</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>I'm a table with tfoot done wrong.</td>
      <td>I'm a table with tfoot done wrong.</td>
    </tr>
    <tr>
      <td>I'm a table with tfoot done wrong.</td>
      <td>I'm a table with tfoot done wrong.</td>
    </tr>
  </tbody>
  <tfoot>
    <th id="th-1">I'm a table with tfoot done wrong.</th>
    <th id="th-2">I'm a table with tfoot done wrong.</th>
  </tfoot>
</table>

Missing head for data table

Description

<thead> is strongly needed if <tbody> is present.

Selector

table:not([role="presentation"]) > caption + tbody,
table:not([role="presentation"]) > tbody:first-child

Test

Missing thead
I'm a table without thead.	I'm a table without thead.
I'm a table without thead.	I'm a table without thead.

<table>
  <caption>Missing thead</caption>
  <tbody>
    <tr>
      <td>I'm a table without thead.</td>
      <td>I'm a table without thead.</td>
    </tr>
    <tr>
      <td>I'm a table without thead.</td>
      <td>I'm a table without thead.</td>
    </tr>
  </tbody>
</table>

th without [scope] or [id]

Description

<th> strongly needs an [id] or a [scope].

References

Selector

th:not([scope], [id])

Test

Need for a [scope] or [id]
I'm a th without [scope] or [id].	I'm a th with [scope].
I'm a td missing something.	I'm a td missing something.
I'm a td feeling well.	I'm a td feeling well.

<table>
  <caption>Need for a [scope] or [id]</caption>
  <thead>
    <tr>
      <th>I'm a th without [scope] or [id].</th>
      <th scope="col">I'm a th with [scope].</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>I'm a td missing something.</td>
      <td>I'm a td missing something.</td>
    </tr>
    <tr>
      <td>I'm a td feeling well.</td>
      <td>I'm a td feeling well.</td>
    </tr>
  </tbody>
</table>

spacer.gif used

Description

Believe me, this still have to be tested.

References

https://www.la-grange.net/2015/03/11/visible

Selector

img[src*="1px.gif"]:not([role="presentation"]),
img[src*="1x1.gif"]:not([role="presentation"]),
img[src*="clear.gif"]:not([role="presentation"]),
img[src*="spacer.gif"]:not([role="presentation"]),
img[src*="dotclear.gif"]:not([role="presentation"]),
img[src*="transparent.gif"]:not([role="presentation"]),
img[src*="pixel-1x1-clear.gif"]:not([role="presentation"])

Test

†

<img src="/static/spacer.gif" alt="Spacer.gif" width="100" height="100"/><span>†</span>

Bad computed value

Description

Don't laugh, shit happens.

Selector

[id*="NaN"],
[id*="null"],
[class*="NaN"],
[class*="null"],
[id*="undefined"],
[class*="undefined"]

Test

Oups, something went wrong.

<p class="undefined">Oups, something went wrong.</p>

JS [href]

Description

The [href] attribute should not start with "javascript". Should probably be a <button> or at least a [role="button"], don't you think? The only exception shall be bookmarklets.

References

https://github.com/Heydon/REVENGE.CSS/blob/master/revenge.css#L165

Selector

a[href^="javascript"]:not([role="button"])

Test

Please use my bookmarklet ;)

<a href="javascript:(function(){a11ycss=document.createElement('LINK');a11ycss.href='https://rawgit.com/ffoodd/a11y.css/master/css/a11y-en.css';a11ycss.rel='stylesheet';a11ycss.media='all';document.body.appendChild(a11ycss);})();">Please use my bookmarklet ;)</a>

# [href]

Description

The [href] attribute is only containing #. Should probably be a <button> or at least a [role="button"], don't you think?

References

https://github.com/Heydon/REVENGE.CSS/blob/master/revenge.css#L165

Selector

a[href="#"]:not([role="button"])

Test

Oh boy, I don't mean anything

<a href="#">Oh boy, I don't mean anything</a>

[style] attribute

Description

Your styles should be driven by a CSS file. That's it. And no, JS shouldn't manipulate styles: it's better to play with classes, for example.

References

Selector

[style]

Test

I'm red. I really feel dirty.

<div style="color: red;">I'm red. I really feel dirty.</div>

Unsecured [target=_blank]

Description

[target="_blank"] links might be used for phishing. This is not actually an accessibility related issue, but everything helping users is welcome.

References*

Selector

[target$="blank"]:not([rel]),
[target$="blank"]:not([rel*="noopener"]),
[target$="blank"]:not([rel*="noreferrer"])

Test

I feel vulnerable…

<a href="/" target="_blank">I feel vulnerable…</a>

Missing [aria-level]

Description

Though [aria-level] is not required by ARIA specification, it's actually better to specify it.

References

Selector

[role="heading"]:not([aria-level])

Test

Heading with undefined level

<strong role="heading">Heading with undefined level</strong>

A label without a [for] attribute

Description

A <label> is labelling something, in theory. Although implicitly labelling form controls is accepted, it's probably better to double-check that form control is really nested in its <label>.

References

Selector

label:not([for])

Test

Guess what?

<label>Guess what?</label>

Mismatching [dir] and [lang] attributes

Description

Some languages — like Arabic or Hebrew — requires a text direction switch usin [dir="rtl"], as default text direction is left-to-right. This also requires to check any in-page language change (marked up with [lang]) in Arabic or Hebrew content to define [dir] too.

References

Selector

[lang="ar"]:not([dir="rtl"]),
[lang="he"]:not([dir="rtl"]),
[lang="ar"] [lang]:not([dir="ltr"]),
[lang="he"] [lang]:not([dir="ltr"]),
[dir="rtl"]:not([lang="ar"], [lang="he"])

Test

Well, I'm kinda disoriented…

<p dir="rtl" lang="en">Well, I'm kinda disoriented…</p>