Does Samsung Tizen support native NFC app. I'd like a native app that sits on the watch to read scanned tag and do a data exchange ?
If it has to be done in html5, does it support NFC data exchange ?
Does Samsung Tizen support native NFC app. I'd like a native app that sits on the watch to read scanned tag and do a data exchange ?
Yes it does. Please refer to the Wearable Native reference
To read a tag you should take a look at the TAG APIs. If you also want to perform data exchange then you should take a look at the Peer to Peer APIs.
If it has to be done in html5, does it support NFC data exchange ?
Similar functionality is supported using the web APIs. Take a look at the NFCTag and NFCPeer interfaces in the Web API reference.
A nice start (Native development) point could be to check the existing tutorials for NFC here.
Here you will find the tutorials for the web APIs.