Audio plugin, best practice

Hello,
I arrive at the final stage of creating the Addon lecjoa.
The creation of the module, sound plugin.
In the concept of operation, websites just have to specify values in localStorage.
And then there are two choices of construction. Either this is the addon, looking into each open page, if there is a localStorage named donne1; either it’s the web page that calls the addon to say that it contains localStorage named" donne1, donne11 …"

What is the best practice?
Addon look each open web page or web page must call addon ?

cordially

P.S. localStorage donne1, is for audio format dna, in adn.js, audio format dna can generate sound from only 6 bytes

It seems it would be more efficient for websites to notify the add-on when they have that storage flag, but I don’t see a huge difference between both options.

Hello,
Thank you for the answer.
I made a proposal to audio plugin
Add On looks, each HTML page open

https://addons.mozilla.org/en-US/firefox/addon/lecjo/

I expect returns to guide the final form of the audio plugin.
I imagine many directions, but I do not know what to choose, to make it the most basic possible to become a benchmark for the construction of future derivatives Addon

Cordially