Update eip-1577.md (#1670)

EIPS/eip-1577.md

@@ -102,7 +102,12 @@ In order to support names that have an IPFS or Swarm hash in their `content` fie
 
 ### Implementation
 
-To support `contenthash`, a new resolver has been developed and can be found [here](https://github.com/ensdomains/resolvers/blob/master/contracts/PublicResolver.sol), which has been deployed at [0xd3ddccdd3b25a8a7423b5bee360a42146eb4baf3](https://etherscan.io/address/0xd3ddccdd3b25a8a7423b5bee360a42146eb4baf3)
+To support `contenthash`, a new resolver has been developed and can be found [here](https://github.com/ensdomains/resolvers/blob/master/contracts/PublicResolver.sol), you can also find this smart contract deployed on :
+
+* Mainnet : [0xd3ddccdd3b25a8a7423b5bee360a42146eb4baf3](https://etherscan.io/address/0xd3ddccdd3b25a8a7423b5bee360a42146eb4baf3)
+* Ropsten : [0xde469c7106a9fbc3fb98912bb00be983a89bddca](https://ropsten.etherscan.io/address/0xde469c7106a9fbc3fb98912bb00be983a89bddca)
+
+Moreover here is a [js implementation](https://github.com/pldespaigne/content-hash) to encode and decode `contenthash`.
 
 ## Copyright
 Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).