[js] data processing error report

make a simple parser using regular expressions. Imported data in textarea did not replace characters successfully
only hope that imported data can replace characters;
matchArry [0] reported an error

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

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>

<body>
    <textarea id="show" spellcheck="true">-sharp </textarea>
    <input type="file" id="file1">
    <input type="button" id="btn" onclick="rec()" value="">
    <script>
        var filein = document.getElementById("file1"),
            showbox = document.getElementById("show");
        filein.addEventListener("change", function () {
            var file = filein.files[0];
            var reader = new FileReader();
            reader.onload = function (e) {
                var data = e.target.result;
                showbox.innerHTML = data;
            };
            reader.readAsText(file, "utf-8");
        });

        function rec() {
            var textarea = document.getElementById("show");

            textarea.innerHTML = main(textarea.value); //

        }

        function main(evt) {
            var char = evt.split("\n");
            var matchArry;
            var html = "";
            var len = char.length;

            for (var i = 0; i < len; iPP) {
                matchArry = char[i].match(/^-sharp\s/); //[""]

                if (matchArry[0]) {
                    switch (matchArry[0]) { //
                        case "-sharp ":
                            html += "<h1>" + add(char[i].substring(2)) + "</h1>";
                            break;
                        default:
                            break;
                    }
                } else  {
                    html += "

" + add(char[i]) + "

"; } } return html; } function add(str) { str = str.replace(/\s/g, ""); return str; } </script> </body> </html>
Jun.30,2022
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1bf6650-31fe1.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1bf6650-31fe1.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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