HTML Code

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>JSON rules — trailing comma</title>
</head>
<body>
  <h1>Trailing comma fails</h1>
  <pre id="out"></pre>
  <script>
    (function () {
      var bad = '{"name":"Ada","age":36,}';
      var lines = [];

      try {
        JSON.parse(bad);
        lines.push("Parsed OK");
      } catch (err) {
        lines.push(err.name);
        lines.push("Trailing comma is invalid");
      }

      document.getElementById("out").textContent = lines.join("\n");
    })();
  </script>
</body>
</html>

Lines: 0 | Characters: 0

Live Preview Auto-refresh on Run

JSON Rules — trailing comma (Try It)