Editing HTML to Markdown

<!DOCTYPE html>
<html>

<head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta charset="utf-8" />
    <title>HTML to Markdown</title>

    <script src="https://netnr.eu.org/turndown@7.2.1/lib/turndown.browser.umd.js"></script>
</head>

<body>
    <textarea></textarea>
    <div><button>HTML to Markdown</button></div>
</body>

</html>

textarea {
    width: 97vw;
    height: 62vh;
}

let turndownService = new TurndownService({
    headingStyle: "atx",
    hr: "---",
    bulletListMarker: "-",
    codeBlockStyle: "fenced",
    fence: "```",
    emDelimiter: "-",
    strongDelimiter: "**",
    linkStyle: "inlined",
    linkReferenceStyle: "full",
    preformattedCode: false
});

let domTxt = document.querySelector('textarea');
let domBtn = document.querySelector('button');
domBtn.addEventListener("click", function () {
    var markdown = turndownService.turndown(domTxt.value);
    console.debug(markdown);
    domTxt.value = markdown;
});