What information does javascript collect?

Question

JavaScript

Firework. Are there any utilities that can show what information the javascript from the site collects about the environment? OS, screen resolution, locale, etc. ?

Answer 1

Firebug will show all network activity. And there you already see what and where it goes.

Answer 2

Look at the window.navigator and window.screen
objects These objects store basic information about the browser, environment, and screen resolution.
And so, look in the console which requests are sent where