examples/browser/ethereum/metamask.html

<html>
<head>
  <script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
  <script src="../../../dist/index.umd.js"></script>
</head>
<body>
  <h1>CAL + MetaMask: Sign a message (Ethereum)</h1>
  <p>From: <span id="address"></span></p>
  <p>Message: <input type="text" id="message"/> <button id="sign">Sign</button></p>
  <p>Result: <span id="result"></span></p>
  <p><code>For errors and logs, check console</code></p>
  <script>
  /* global $, web3, ChainAbstractionLayer */
  const { Client, providers } = ChainAbstractionLayer
  const ethereum = new Client()
  ethereum.addProvider(new providers.ethereum.EthereumMetaMaskProvider(web3.currentProvider))
  ethereum.getAddresses().then(addresses => {
    const from = addresses[0]
    $('#address').text(from)

    $('#sign').click(() => {
      ethereum.signMessage($('#message').val(), from).then(result => {
        $('#result').text(JSON.stringify(result))
      })
    })
  })
  </script>
</body>
</html>