Desktop Chrome and FF do not support HLS. I know there is a plugin available to add HLS support to flash. Is there such plugin or technique available to enhance HTML5 on browsers which dont have HLS support yet?
Not only it is possible, but it's been done numerous times. There are several open and closed source solutions available. A quick github search gave me this one.
https://github.com/RReverser/mpegts
EDIT: New/better option just released http://engineering.dailymotion.com/introducing-hls-js/