viewer.html

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title></title>
    <style>
        * {
            margin: 0;
            padding: 0;
            overflow: hidden;
        }

        #container {
            display: flex;
            flex-direction: row;
            flex-wrap: wrap;
            align-items: center;
            justify-content: center;
            background-color: rgb(198, 226, 255);
            object-fit: scale-down;
        }

        #cam {
            width: 100vw;
            height: 100vh;
        }
    </style>
</head>

<body>
    <div id="container">
        <div id="box-content">
            <img id="cam" src="" onclick="change_style();">
        </div>
    </div>
</body>
<script>
    window.onload = function (evt) {
        var address = prompt("Enter address", "http://localhost:8080");
        document.getElementById("cam").src = address;
    }
    var idx = 0;
    var stls = ["contain", "cover", "fill", "scale-down"]

    function change_style() {
        idx = idx + 1;
        idx = (idx) % stls.length;
        document.getElementById("cam").style.objectFit = stls[idx];
        console.log(stls[idx])
    }
</script>

</html>