Importing ECDSA public key from javascript/subtlecrypto

Hello general@,

For a project I'm working on I need to import an ECDSA public key into  
the openssl extension to verify data/signatures send by the client. The 
key has been verified, so that's no problem.

The problem is the fact that subtlecrypto exports the key as raw, spki,
or jwk, while non of these can be imported into the openssl extension.

Can anyone inform me on a way to make the key compatible with the
openssl interface, be it on the javascript side or the php side.

Sincerely,

Martijn van Duren