Is it possible to access NFC API in HTML5 applications?
There is an API out there, but there is no browser release supporting this API due to the lack of its development!
As an update to the above. The latest Chrome Canary for Android does now support WebNFC. Interestingly, the primary Chrome supports the older protocol of the NFC.watch method which allows for data to be read/written but the new one has changed to NFCReader methods which are promise based which you start and stop. The later allows for reading of the ID. https://w3c.github.io/web-nfc/
The Web NFC API (maintained by the NFC Working Group is currently in draft status. This API is intended to provide access to NFC functionality for HTML5.
BUT
- In its current version the NFC Web API does not provide any means to get a tags ID/serial numer/anti-collision identifier (I assume that's what you mean with ID, right?). In fact the API will only provide access to NFC tags through the NDEF abstraction layer.
- I don't know of any browser release that currently implements the NFC Web API.
UPDATE
The NFC Working Group was closed after its charter expired (mainly due to lack of support by browser vendors) and is no longer maintaining the specification. Instead there is a Web NFC Community Group now that maintains the Web NFC API specification now.