const hash = { /* ... passed from the server-side .... */ };

if (!window.web3) return alert('you don\'t have metamask installed');

// call web3 code from the client-side like so
const abi = [ /* ... */ ]
const contract = web3.eth.contract(abi).at('0x12323.....');

contract.claimReward(
    1000, 1, 123,                           // pass the parameters
    hash.data,                              // the hash of all the parameters
    hash.hash.v, hash.hash.r, hash.hash.s,  // the signed hash
    (error, results) => console.log(error, results)
)