Malayalam wikipedia do not have built in support for inscript keyboard.
However, You can install inscript support to your favorite operating system.

If you are using Microsoft Windows; please have a look at http://malayalamresourcecentre.org/malayalamkeyboard/index.html . It explains how to install Inscript support win MS Windows XP.

If you are on a Linux box (for example Ubuntu); it should support Inscript by default.
http://malayalam.kerala.gov.in/index.php/%E0%B4%AA%E0%B5%8D%E0%B4%B0%E0%B4%A7%E0%B4%BE%E0%B4%A8%E0%B4%A4%E0%B4%BE%E0%B4%B3%E0%B5%8D%E2%80%8D this link may help you for configuring it.

Regards
Praveen