シフトJIS文字表 #JavaScript

TextDecoder を使用してシフトJISコードを Unicode に変換して表示します。
表示されるものはブラウザにある変換表次第になります。
See the Pen シフトJIS文字表 by Ikiuo (@ikiuo) on CodePen.
<!DOCTYPE html>
<html lang="ja">
  <head>
    <meta charset="utf-8">
    <title>シフトJIS文字表</title>
    <style>
     body {
         margin: auto;
         width: 750px;
     }
     table {
         border: solid 0px;
         border-left: solid 1px lightgray;
         border-top: solid 1px lightgray;
         border-collaspe: collaspe;
         border-spacing: 0;
     }
     th, td {
         border: solid 0px;
         border-right: solid 1px lightgray;
         border-bottom: solid 1px lightgray;
         padding: 4px;
     }
     th {
         background-color: #eeeeee;
     }
     td {
         text-align: center;
     }
     .undef {
         background-color: #ffeeff;
     }
    </style>
  </head>
  <body>
    <script>

     window.onload = function() {
         const td_unassigned = '<td class="undef">&nbsp;</td>';

         const decoder = new TextDecoder('sjis');
         const buffer = new ArrayBuffer(2);
         const view = new DataView(buffer);
         const sjis = new Map();
         const hcode = [];

         for (let y = 0xa1; y <= 0xdc; ++y) {
             const h = y ^ 0x20;
             let has = false;

             view.setUint8(0, h);
             for (let l = 0x40; l <= 0xfc; ++l) {
                 if (l == 0x7f)
                     continue;
                 view.setUint8(1, l);

                 const us = decoder.decode(view);
                 if (us.length < 1)
                     continue;
                 if (us.charCodeAt(0) == 0xfffd)
                     continue;
                 sjis.set(view.getUint16(0, false), us);
                 has = true;
             }
             if (has)
                 hcode.push(h);
         }

         html = '<table border="1">';
         html += '<tr><th colspan="17">シフトJIS文字表</th></tr>';
         for (const h of hcode) {
             const hh = h << 8;
             html += '<tr><th>&nbsp;</th>';
             for (let x = 0; x < 16; ++x)
                 html += `<th>${x.toString(16).toUpperCase()}</th>`;
             html += '</tr>';
             for (let lp = 0x40; lp <= 0xfc; lp += 16) {
                 const scode = hh + lp;
                 html += `<tr><th>${scode.toString(16).toUpperCase()}</th>`;
                 for (let x = 0; x < 16; ++x) {
                     const us = sjis.get(scode + x);
                     if (!us)
                         html += td_unassigned;
                     else
                         html += `<td>${us}</td>`;
                 }
                 html += '</tr>';
             }
         }
         html += '</table>'

         document.body.innerHTML = html;
     }

    </script>
  </body>
</html>