Hiding content is very useful for accessibility. We can hide things visually from the browser display and only reveal it to assistive technology (AT) like screen readers. We can hide content from AT users and only show it visually in the browser. And we can hide content from both.
It is sometimes helpful to add textual information or cues intended only for assistive technology (AT) users. To hide this text from the visual display but make it available to AT, this is the recommended CSS method:
.visually-hidden:not(:focus):not(:active) {
clip: rect(0 0 0 0);
clip-path: inset(100%);
height: 1px;
overflow: hidden;
position: absolute;
white-space: nowrap;
width: 1px;
}
At ASU, we use this method to hide the "Skip to main content" link at the top of all ASU web pages.
<a href="#skip-to-content" class="sr-only sr-only-focusable">
Skip to main content
</a>
When design mockups require you to use repetitive links such as "Read more," you can still make them accessible by providing important destination information for AT users:
<a href="#trees">
Read more
<span class="visually-hidden">
about maple trees
</span>
</a>
You can also use this method to supply labels for field inputs where the design does not provide for visual labels. This example from Scott O'Hara's Inclusively Hidden is an excellent illustration:
<fieldset class="date-range-component">
<legend>
Select Start and End Dates
</legend>
<label for="start_date" class="visually-hidden">
Start Date:
</label>
<input type="date" id="start_date" name="start_date">
<span> to </span>
<label for="end_date" class="visually-hidden">
End Date:
</label>
<input type="date" id="end_date" name="end_date">
</fieldset>
Conversely, if you want to hide content from AT but not from visual display, use: aria-hidden="true" For example, we often hide decorative Font Awesome icons this way:
<h2>
<span class="fa fa-caret-right" aria-hidden="true"></span>
Start for Free
</h2>
However, be very careful about hiding visible content from AT users. Only hide elements if it improves the experience for AT users by removing purely decorative, redundant or duplicated content.
The CSS properties display: none; or visibility: hidden will hide an element from both AT and visual display. The HTML hidden property does the same.There are subtle differences to each of these--see Scott O'Hara's excellent Inclusively Hidden for an in-depth discussion.
The most common use for these properties is for toggling a hidden/shown state with Javascript on accordions, sliders, carousels, and other complex widgets.
CSS background images often are used to separate style (decorative images) from content (text or information). Sometimes it's necessary to use a CSS background technique to add meaningful images that convey information, such as logos, functional icons, or buttons.
Please note: If the image is decorative (that is, doesn't convey any meaningful information), you should not supply a text alternative for the image.
When an image conveys meaning, you must supply alternative text describing the function of the image for screen reader users, while hiding it visually.
To accomplish this, use an accessible CSS replacement technique. The method below was adapted from Bootstrap:
.meaningful-bg-img {
font: 0/0 a;
color: transparent;
text-shadow: none;
background-color: transparent;
border: 0;
text-decoration: none;
background-image: url('/sites/default/files/inline-images/logo_1.png');
width: 110px;
height: 100px;
display: block; /* display:inline-block also works */
}
<h1 class="meaningful-bg-img">XYZ Yacht Company</h1>
<h1><a class="meaningful-bg-img" href="index.html">XYZ Yacht Company</a></h1>
