* Proposal * fix(review)
5.2 KiB
layout | title | description | group | toc | added |
---|---|---|---|---|---|
docs | Placeholders | Use loading placeholders for your components or pages to indicate something may still be loading. | components | true | 5.1 |
About
Placeholders can be used to enhance the experience of your application. They're built only with HTML and CSS, meaning you don't need any JavaScript to create them. You will, however, need some custom JavaScript to toggle their visibility. Their appearance, color, and sizing can be easily customized with our utility classes.
Example
In the example below, we take a typical card component and recreate it with placeholders applied to create a "loading card". Size and proportions are the same between the two.
Card title
Some quick example text to build on the card title and make up the bulk of the card's content.
Go somewhere<div class="card">
<img src="..." class="card-img-top" alt="...">
<div class="card-body">
<h5 class="card-title">Card title</h5>
<p class="card-text">Some quick example text to build on the card title and make up the bulk of the card's content.</p>
<a href="#" class="btn btn-primary">Go somewhere</a>
</div>
</div>
<div class="card" aria-hidden="true">
<img src="..." class="card-img-top" alt="...">
<div class="card-body">
<h5 class="card-title placeholder-glow">
<span class="placeholder col-6"></span>
</h5>
<p class="card-text placeholder-glow">
<span class="placeholder col-7"></span>
<span class="placeholder col-4"></span>
<span class="placeholder col-4"></span>
<span class="placeholder col-6"></span>
<span class="placeholder col-8"></span>
</p>
<a class="btn btn-primary disabled placeholder col-6"></a>
</div>
</div>
How it works
Create placeholders with the .placeholder
class and a grid column class (e.g., .col-6
) to set the width
. They can replace the text inside an element or be added as a modifier class to an existing component.
We apply additional styling to .btn
s via ::before
to ensure the height
is respected. You may extend this pattern for other situations as needed, or add a
within the element to reflect the height when actual text is rendered in its place.
{{< example >}}
{{< /example >}}
{{< callout info >}}
The use of aria-hidden="true"
only indicates that the element should be hidden to screen readers. The loading behavior of the placeholder depends on how authors will actually use the placeholder styles, how they plan to update things, etc. Some JavaScript code may be needed to swap the state of the placeholder and inform AT users of the update.
{{< /callout >}}
Width
You can change the width
through grid column classes, width utilities, or inline styles.
{{< example >}} {{< /example >}}
Color
By default, the placeholder
uses currentColor
. This can be overridden with a custom color or utility class.
{{< example >}} {{< placeholders.inline >}} {{- range (index $.Site.Data "theme-colors") }} {{- end -}} {{< /placeholders.inline >}} {{< /example >}}
Sizing
The size of .placeholder
s are based on the typographic style of the parent element. Customize them with sizing modifiers: .placeholder-lg
, .placeholder-sm
, or .placeholder-xs
.
{{< example >}} {{< /example >}}
Animation
Animate placeholders with .placeholder-glow
or .placeholder-wave
to better convey the perception of something being actively loaded.
{{< example >}}
{{< /example >}}
Sass
Variables
{{< scss-docs name="placeholders" file="scss/_variables.scss" >}}