index.html


        <!DOCTYPE html>
        <html lang="en">
        <body>
        <h3>Enter a number in the appropriate boxes to get the return values from the functions</h3>
        
        <div>
            <input type="text" id="fib">Sum of Fibonacci: Enter a non-negative integer</input>
            <button onclick="httpGet(1)">Send Request</button>
        </div><br><br>
        <div>
            <input type="text" id="factorial">Factorial: Enter a non-negative number</input>
            <button onclick="httpGet(2)">Send Request</button>
        </div><br><br>
        <div>
            <input type="text" id="ackermann1">Ackermann function: Enter 1st non-negative number</input><br>
            <input type="text" id="ackermann2">Ackermann function:Enter 2nd non-negative number</input>
            <button onclick="httpGet(3)">Send Request</button>
        </div><br><br>
        
        <h4>Solution:</h4>
        <div id="output"></div>
        
        <script>
            var output = document.getElementById('output');
        
            function httpGet(func_call) {
                let xmlHttp = new XMLHttpRequest();
                if (func_call === 1) {
                    xmlHttp.open("GET", "https://7p7narmief.execute-api.eu-central-1.amazonaws.com/Prod/fib/" + document.getElementById("fib").value, false);
                } else if (func_call === 2) {
                    xmlHttp.open("GET", "https://7p7narmief.execute-api.eu-central-1.amazonaws.com/Prod/factorial/" + document.getElementById("factorial").value, false);
                } else if (func_call === 3) {
                    let ackermann_url_string = "https://7p7narmief.execute-api.eu-central-1.amazonaws.com/Prod/ackermann/" + document.getElementById("ackermann1").value + '-' + document.getElementById("ackermann2").value;
                    xmlHttp.open("GET", ackermann_url_string, false);
                }
                xmlHttp.send(null);
                let returnValue = xmlHttp.responseText;
                output.innerHTML = returnValue;
            }
        </script>
        
        </body>
        </html>
    