Skip to content

[css-mediaqueries-5] nav-controls: Clarify use in a boolean context (closes #7288) #6795

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 1 commit into
base: main
Choose a base branch
from
Open

[css-mediaqueries-5] nav-controls: Clarify use in a boolean context (closes #7288) #6795

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
24 changes: 5 additions & 19 deletions mediaqueries-5/Overview.bs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2273,25 +2273,11 @@ Detecting UA-supplied navigation controls: the 'nav-controls' feature</h3>
}
}</code></pre>

As this media feature can be used in a [=boolean context=],
the same example can be written with shorter syntax:

<pre><code class=lang-css>
@media (nav-controls) {
#back-button {
display: none;
}
}</code></pre>

Note: Theoretically, the two are not strictly equivalent,
as there could be new values in a future extension of this media feature
other than ''back''
that could match when ''back'' doesn't.
In that case, using the 'nav-controls' feature in a boolean context could be misleading.
However, given that navigation back is arguably the most fundamental navigation operation,
the CSS Working Group does not anticipate
user interfaces with explicit navigation controls but no back button,
so this problem is not expected to occur in practice.
Note: This media feature can also be used in a [=boolean context=], e.g.,
<code class=lang=css>@media (nav-controls)</code>. However, as there could be new values in a future
extension of this media feature other than ''back'', use of the ''nav-controls'' feature in a boolean
context could cause the page to incorrectly interpret some other control as a "back" button, and its
usage is therefore discouraged.
</div>

Whether [=obviously discoverable=] controls are active does not impact the evaluation of this media feature.
Expand Down