load_test.js

function fetchCall() {
    const Http = new XMLHttpRequest();
    const host = window.location.href.substring(0, window.location.href.indexOf(window.location.pathname));
    const url = host + "/?file=1mb";
    Http.open("GET", url);
    Http.send();
    Http.onreadystatechange = (e) => {
        if (Http.readyState == XMLHttpRequest.DONE) {
            document.getElementById("test_result").value = document.getElementById("test_result").value +
                "\nReceived data, chunks remaining: " + _chunks;
            console.log('Received data, chunks remaining: ' + _chunks);
            console.log('Ready state: ' + Http.readyState);
            if (_chunks > 0) {
                _chunks--;
                fetchCall();
            }
            else {
                var endTime = Date.now();
                var elapsed_time = endTime - _startTime;
                var speed = Math.round((10 * 8) / (elapsed_time / 1000.0));
                document.getElementById("test_result").value =
                    document.getElementById("test_result").value + "\nTime: " + elapsed_time / 1000.0 + "\nSpeed: " + speed + " Mbps";
            }
        }
    }
}