Sure it can. There's also a php API which I linked in one of the older comments. You can use either of these to create your own web client.

Someone ported the php implementation to Nodejs and made a working web client but it's broken now and is no longer maintained IIRC.

http://whatsapp.filshmedia.net/

You can take a look at its github repo and fix it yourself if you're familiar with Nodejs.