title: how to get transaction history from blocks via web3?
body: <p>I have a private chain now and I want to query the transaction histories.I know that web3 has provide those methods <strong>web3.eth.blockNumber</strong>/<strong>web3.eth.getBlockTransactionCount</strong>/<strong>web3.eth.getTransactionFromBlock</strong>. So I can get the transactions history by get latest blocknumber(suppose it's n). Range from n to 0 to call web3.eth.getBlockTransactionCount(i), then get transactions by web3.eth.getTransactionFromBlock. but it's just time wasting and inefficient.
  so I'm wondering how can I get transaction histories from blocks efficient via web3 or rpc or anyway?</p>