JavaScriptでnative2ascii

変換ツール（ native ⇔ ascii ）
サンプルHTML
変換ツール（ native ⇔ ascii ）

変換対象

変換結果
サンプルHTML

<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
    <title>JavaScriptでnative2ascii</title>
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
    <script type="text/javascript">
    $(function() {
        
        $("#n2a").click(function() {
            
            var raw = $("#in").val();
            var result = "";
            
            while(true){
                if (raw.length == 0) break;
                var t = raw.substring(0,1);
                raw = raw.substring(1);
                var tmp = t.charCodeAt().toString(16);
                if (tmp.length >= 4) {
                    result += "\\u" + tmp;
                } else {
                    result += t;
                }
            }
            $("#out").val(result);
        });
        
        $("#a2n").click(function() {
            var raw = $("#in").val();
            var result = "";
            while(true) {
                if (raw.length == 0) break;
                var index = raw.indexOf("\\u");
                if (index == -1) {
                    result += raw;
                    break;
                }
                if (0 < index) {
                    result += raw.substring(0, index);
                }
                if (index + 6 <= raw.length) {
                    var tmp = parseInt(raw.substring(index + 2, index + 6), 16);
                    result += String.fromCharCode(tmp);
                    raw = raw.substring(index + 6);
                } else {
                    break;
                }
            }
            $("#out").val(result);
        });
    });
    </script>
</head>
<body>
    <h2>JavaScriptでnative2ascii</h2>
    変換対象<br/>
    <textarea id="in" style="width:800px;height:80px;"></textarea><br/>
    <input type="button" id="n2a" value="native2ascii">
    <input type="button" id="a2n" value="ascii2native"><br />
    変換結果<br/>
    <textarea id="out" style="width:800px;height:80px;"></textarea><br/>        
</body>
</html>