What is/are the best (Performance efficient) ways to integrate Web/HTML5 within Unity3d?

I am working on a Unity app which requires me to have a library of HTML5 minigames to be played within Unity app. I tried some plugins from asset store which open native browsers in mobile devices, it does work, but cause major framerate drop which is unacceptable. All the games if played directly on browsers have no lag.

Is there a better solution or implementation? How can the lag be overcome?

Thank you