Extension:PopupAlerts

The PopupAlerts extension allows to add popup alerts to wiki pages with an optionally specified expiration date so it can be controlled when (and if) users will see the popup again. It also has an integrated checksum-based invalidation mechanism to detect popup content change and hence reset the “already-seen” markers.

Download
You can download the External Data code, in .zip format, here.

You can also download the code directly via Git from the MediaWiki source code repository. From a command line, you can call the following:

You can also view the code online here.

Installation
To install this extension, create a 'PopupAlerts' directory (either by extracting a compressed file or downloading via Git), and place this directory within the main MediaWiki 'extensions' directory. Then, in the file 'LocalSettings.php', add the following line:

Usage
popup will be seen once in 100 years

popup will be seen once in one hour (3600 seconds)

Note: If you have many popups added to the page, only the first one will be taken into account. This limitation was added intentionally to prevent wiki pages from being spammed with popups.