No and you can't verify it somehow. Generally, generating random numbers using javascript through a web browser isn't recommended. Once you want to keep your funds safe, you have to ensure that nothing malicious has being involved in the process of the entropy's generation. Theoretically, a malware/virus could affect your computer's RNG and return you results that may seed random, but they're not.

I'd advice you to use tangible and physical things whose randomness could be verified like a coin's or even better (for your time), a dice's.

Take a look: [Open Source] Coin Flipped Seed (coin flip, dice roll, rubik's cube mixing)