start . me .
Directory path . web , tools .

HTML Document File : origin.html 

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

<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title> fetch and show-source </title>
    <link rel="stylesheet" href="/sitewide.css"><script src="/web/dhtml/color-theme/colors.js"></script>
</head>

<body>

    <input id="address" oninput="content_of(this.value)" placeholder="address">

    <script>
        function content_of(url) {
            fetch(url).then(res => res.text()).then(res => content.textContent = res)
        }
        content_of("")
    </script>

    <pre id="content"></pre>

    <script src="/web/show-source.js"></script>

</body>

</html>