Manual:Force preview

Force preview is a javascript that prevents specified individuals or groups from saving a wiki page before they preview it at least once. The below scripts are based on Marc Mongenet's script, from.

Force preview by wgUserGroups, requires a MW version >= 1.10
'''Can someone please explain how to implement this with MediaWiki 1.11? Is this inserted in Localsettings.php? Elsewhere? Thank you.'''