mac.html

<!DOCTYPE HTML>
<html>
<head>
    <meta charset="UTF-8" />
    <title>FFMZ IP2MAC</title>
    <script type="text/javascript">
        function dec2hex(i)
        {
            var res = "error";
            if (i >= 0 && i <= 15)
            {
                res = "0" + Number(i).toString(16);
            }
            else if (i >= 16 && i <= 255)
            {
                res = Number(i).toString(16);
            }
            return res;
        }

        function conv(v, field)
        {
            var f = document.getElementById(field);
            f.innerHTML = dec2hex(v)
        }

    </script>
</head>
<body>

<form>10.37.<input type="text" onKeyUP="conv(this.value, 'a')" size="3" maxlength="3" />.<input type="text" onKeyUP="conv(this.value, 'b')" size="3" maxlength="3" /></form>

<p>
    02:00:0a:25:<span id="a">??</span>:<span id="b">??</span>
</p>

</body>
</html>