Web3j send ERC20 Token Demo - 区块链中文技术社区

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <script src="../../libs/web3.js_v1.0.0-beta.35/web3.min.js"></script>
</head>
<body>

  <h1>Send ERC20 Token</h1>

  <h2>Notes</h2>
  <ul>
    <li>Use MetaMask</li>
    <li>To check ERC20 balance, use <a href="../getERC20TokenBalance/" target="_blank">getERC20TokenBalance</a></li>
  </ul>

  <h2>Token Address</h2>
  <input type="text" id="token-address" size="80" oninput="onAddressChange()"></input>
  <p>e.g. 0x2A65D41dbC6E8925bD9253abfAdaFab98eA53E34</p>

  <h2>Recipients Address</h2>
  <input type="text" id="to-address" size="80"></input>
  <p>e.g. 0x8Df70546681657D6FFE227aB51662e5b6e831B7A</p>

  <h2>Decimals</h2>
  <input type="number" id="decimals" size="40" readonly></input>

  <h2>Amount</h2>
  <input type="number" id="amount" size="40"></input>

  <div><button id="send" onclick="send()">Send ERC20 Token</button></div>

  <h2>Result</h2>
  <span id="result"></span>

  <script>

    var web3js;
    var account;

    function getERC20TokenBalance(tokenAddress, walletAddress, callback) {
      let minABI = [
        {"constant":true,"inputs":[{"name":"_owner","type":"address"}],"name":"balanceOf","outputs":[{"name":"balance","type":"uint256"}],"type":"function"},
        {"constant":true,"inputs":[],"name":"decimals","outputs":[{"name":"","type":"uint8"}],"type":"function"}
      ];
      let contract = new web3js.eth.Contract(minABI, tokenAddress);
      contract.methods.balanceOf(walletAddress).call((error, balance) => {
        contract.methods.decimals().call((error, decimals) => {
          console.log(balance);
          console.log(decimals);
          balance = balance / (10**decimals);
          callback(balance);
        });
      });
    }

    function getERC20TokenContract(tokenAddress) {
      let minABI = [
        {"constant":true,"inputs":[{"name":"_owner","type":"address"}],"name":"balanceOf","outputs":[{"name":"balance","type":"uint256"}],"type":"function"},
        {"constant":true,"inputs":[],"name":"decimals","outputs":[{"name":"","type":"uint8"}],"type":"function"},
        {"constant":false,"inputs":[{"name":"_to","type":"address"},{"name":"_value","type":"uint256"}],"name":"transfer","outputs":[{"name":"","type":"bool"}],"type":"function"}
      ];
      return new web3js.eth.Contract(minABI, tokenAddress);
    }

    function getERC20TokenDecimals(callback) {
      window.tokenContract.methods.decimals().call((error, decimals) => {
        callback(decimals);
      });
    }

    function onAddressChange(e) {
      let tokenAddress = document.getElementById('token-address').value;
      if(tokenAddress != "") {
        window.tokenContract = getERC20TokenContract(tokenAddress);
        getERC20TokenDecimals((decimals) => {
          document.getElementById('decimals').value = decimals;
        });
      }
    }

    function transferERC20Token(toAddress, value, callback) {
      window.tokenContract.methods.transfer(toAddress, value).send({from: account})
      .on('transactionHash', function(hash){
        callback(hash);
      });
    }

    function send() {
      var toAddress = document.getElementById('to-address').value;
      var decimals = web3js.utils.toBN(document.getElementById('decimals').value);
      var amount = web3js.utils.toBN(document.getElementById('amount').value);
      var sendValue = amount.mul(web3js.utils.toBN(10).pow(decimals));
      console.log(sendValue.toString());
      transferERC20Token(toAddress, sendValue, (txHash) => {
        document.getElementById('result').innerText = txHash;
      });
    }

    window.onload = function() {
      web3js = new Web3(Web3.givenProvider);
      console.log(web3js.version);
      var accountInterval = setInterval(function() {
        web3js.eth.getAccounts((error, address) => {
          if (address[0] !== account) {
            account = address[0];
            console.log(account);
          }
        });

      }, 300);
    }

  </script>

</body>
</html>
https://github.com/piyolab/sushiether/commit/e35e949b5d898d357f9bd1d4e3f35b679974f192
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