app.js

## app.js
function renderTemp(data) {
  var el = document.getElementById('temperature');
  el.innerHTML = data.temperature + " °C";
}

// replace with the endpoint created in your deployment.
var endpoint = 'http://localhost:3000/weather';

fetch(endpoint, { mode: 'cors' })
  .then(function (resp) {
    return resp.json();
  })
  .then(renderTemp);

## index.html
<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>What is the temperature?</title>
  <style>
    h1,
    h2 {
      text-align: center;
      font-family: sans-serif;
      color: #333;
    }
  </style>
</head>

<body>
  <h1>What is the temperature?</h1>
  <h2 id='temperature'>Checking...</h2>

  <script src="app.js" charset="utf-8"></script>
</body>

</html>

## weather.js
module.exports.getWeather = (event, context, callback) => {
  const data = { temperature: 19.2 };

  const response = {
    statusCode: 200,
    headers: {
      "Access-Control-Allow-Origin": "*",
    },
    body: JSON.stringify(data)
  };

  callback(null, response);
};