change secp256k1 to p256, signature and verify don't work

[xiawu]

I change the following code in the point.js :

//var ec = require('elliptic').curves.secp256k1;
var ec = require('elliptic').curves.p256;

After it, I try the following code, sign and verify don't work

var ecdsa = new ECDSA();
  ecdsa.hashbuf = Hash.sha256(new Buffer('test data'));
  ecdsa.privkey = new Privkey(BN.fromBuffer(
    new Buffer('fee0a1f7afebf9d2a5a80c0c98a31c709681cce195cbcd06342b517970c0be1e', 'hex')
  ));
  ecdsa.privkey2pubkey();

ecdsa.signRandomK();
console.log("ecdsa.sig: " + ecdsa.sig);
var ecdsa2 = ECDSA(ecdsa);
ecdsa2.signRandomK();
console.log("ecdsa2.sig: " + ecdsa.sig.toString());

ecdsa.sig = Signature.fromString('304402205593283cd1612fe9dd62e922c6eba85161c36f32c3ea865f68c954cc57e80792022039f579b5bc8b1a936ceec66b46ff8c3c6635056fca82b58ab0769b52c8d2153a');
var status = ecdsa.verify().verified;
console.log("status:" + status);

thanks for any suggestions.

@petertodd