browser capabilities webgl wasm storage
Asking "which browser is this?" through the User-Agent string is fragile, because that string can be changed and is already being deliberately reduced; the correct practice is asking "does this feature exist?" directly to the browser object, checking `'geolocation' in navigator` or `typeof WebAssembly !== 'undefined'` instead of trying to guess from a name. This page live-tests support for storage, WebGL, WebAssembly, Service Worker and clipboard in your browser.
When the context returns an object instead of `null`, the graphics card and system driver support 3D acceleration through the browser, unlocking advanced canvas work, maps and client-rendered games.
Outside HTTPS or localhost, the browser does not even expose the `clipboard` object, so testing its presence already filters out the most common problem before attempting a programmatic copy or paste.
In some browsers and versions, the storage quota in private mode is deliberately reduced to zero, so an actual write test is more reliable than just checking `typeof localStorage`.
User-Agent is a string sent by the browser in HTTP requests and exposed via JavaScript. It usually includes browser, engine, operating system and historical compatibility tokens.
Because the browser name guarantees nothing about version, platform or granted permissions: two users on the same Chrome build can have geolocation available or not depending on the operating system and configuration; checking the API own presence answers exactly the question that matters, without depending on an external compatibility table that goes stale.
All current major browsers (Chrome, Firefox, Safari, Edge) support WebAssembly, but testing `typeof WebAssembly !== 'undefined'` is still worth doing to cover older embedded browsers, such as some outdated mobile app WebViews that still circulate in production.
It rarely disables them entirely: the more common pattern is reducing quota or behavior, such as zeroing the `localStorage` quota in private browsing on older browsers, instead of removing the whole API; that is why testing only for the object existence is not enough, the actual operation needs to be tested.
Because the browser treats reading from the clipboard, which always needs explicit user permission due to the risk of leaking sensitive data, differently from writing to it in direct response to a user gesture, such as a click, which many browsers allow without an extra prompt since it is an action the user themselves triggered.
Reading happens locally and does not send User-Agent, timezone or capabilities to analytics.