Web Crypto API allows creating ECC keys with some known curves: https://developer.mozilla.org/en-US/docs/Web/API/EcKeyGenParams
Those are P-256, P-384, P-521.
However as answered at this answer https://crypto.stackexchange.com/a/30273/99862
There are secp256k1, and secp256r1, and maybe more?
Which is the exact P-256
implemented by Web Crypto API?