index.html

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8"/>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <meta name="mobile-web-app-capable" content="yes">
    <meta name="apple-mobile-web-app-capable" content="yes">
    <title>Chess</title>
    <link rel="stylesheet" href="chessboard.css"/>
    <script src="jquery.js"></script>
    <style>
        @media (orientation: landscape) {
            #board {
                width: 75vh;
            }
        }
        @media (orientation: portrait) {
            #board {
                width: 95vw;
            }
        }
    </style>
</head>
<body>
    <div id="board"></div>
    <script src="chessboard.js"></script>
    <script>
        var board = Chessboard("#board", {
            draggable: true,
            position: prompt("Enter fen: ", "start"),
            onChange: (oldPos, newPos) => console.log(Chessboard.objToFen(newPos)),
            dropOffBoard: "trash",
            sparePieces: true
        });
    </script>
</body>
</html>