wfMobileDetect()

If you would like to set a default theme depending on a visitor's browser, you can add this to your LocalSettings.php:

wfLoadExtension( 'MobileDetect' );
$mobile = wfMobileDetect();
if ( $mobile ) {
    $wgDefaultSkin = "chick"; # If mobile
} else {
    $wgDefaultSkin = "vector"; # If not mobile
}

With this code, if the visitor's browser shows a user agent from a mobile browser, the default theme will be "chick" instead of "vector". If instead the browser shows a user agent from a desktop/full browser, the default theme will be "vector" instead of "chick".

If you would like a certain extension to be excluded from loading on mobile browsers, you can add this to your LocalSettings.php:

wfLoadExtension( 'MobileDetect' );
$mobile = wfMobileDetect();
if ( ! $mobile ) {
    wfLoadExtension( 'ConfirmEdit' ); # Only load if desktop browser
}

With this code, the reCAPTCHA extension would only load on desktop/full browsers.

‎<nomobile> and ‎<mobileonly> tags

The MobileDetect extension also introduces the ‎<nomobile> and ‎<mobileonly> tags, which allow users to control which content is displayed in mobile browsers, and which in desktop/full browsers. Whatever is wrapped between ‎<mobileonly> tags will only be displayed in mobile browsers, and whatever is wrapped between ‎<nomobile> tags will only be displayed in desktop/full browsers. So for example:

<mobileonly>This will not be displayed in desktop/full browsers, only in mobile browsers</mobileonly>
<nomobile>This will not be displayed in mobile browsers, only in desktop/full browsers</nomobile>

The naming and behaviour of the ‎<mobileonly> and ‎<nomobile> tags follows that of the ‎<includeonly> and ‎<noinclude> tags.

#nomobile and #mobileonly parser functions

The MobileDetect extension also introduces the #nomobile and #mobileonly parser functions, which work exactly like the ‎<nomobile> and ‎<mobileonly> tags, with the difference that their content gets parsed so they can contain stuff like {{{1}}} and be used in templates.

However, they don't render all multi-line content correctly, so use them mostly for inline content.

nomobile and mobileonly classes

Alternatively, it is also possible to use the CSS classes directly:

{| class="wikitable nomobile"
|- 
| (Some wikitable stuff.)
|}