index.html

<!DOCTYPE html>

<html lang="en">
<head>
 <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <title>Duco Faucet</title>
</head>
<body>
  <!--claim-->
    <script>
            const serveraddress = "YOUR IP"
        
            function claim() {
                username = document.getElementById("usernameInput").value
            
                xhr = new XMLHttpRequest();
                xhr.open("GET", "http://" + serveraddress + "/claim/" + username);
                xhr.onloadend = function () { alert(xhr.responseText); document.getElementById("claimresult").innerHTML = xhr.responseText;};
                xhr.send();
                document.getElementById("claimresult").innerHTML = "Sucessful"
            }
        </script>
<!--claim-->   
  <span>Username : </span><input id="usernameInput" type="text"></input>
                    <button onclick="claim()">Claim</button>
                    <div id="claimresult"></div>
  </body>
</html>