Temperature: <span id="temperature"></span>
<p>
Humidity: <span id="humidity"></span>

<script>
  function loadDoc() {
    // url of gov weather data
    var url = "https://data.weather.gov.hk/weatherAPI/opendata/weather.php?dataType=rhrread&lang=en";
    // create a new XMLHttpRequest object
    var xhttp = new XMLHttpRequest();
    // function to be called when the request is completed
    xhttp.onreadystatechange = function() {
      // check if the request is completed and the response is ready (code 200)
      if (this.readyState == 4 && this.status == 200) {
        var data = JSON.parse(this.responseText);
        // display the temperature
        document.getElementById("temperature").innerHTML = data.temperature.data[1].value;
        // display the rainfall
        document.getElementById("humidity").innerHTML = data.humidity.data[0].value;
      }
    };

    // open a new request
    xhttp.open("GET", url, true);
    // send the request
    xhttp.send();
  }

  // call the function to load the data
  loadDoc();
</script>