HTML Code

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>catch() after throw</title>
</head>
<body>
  <h1>catch() handles thrown errors</h1>
  <pre id="out"></pre>
  <script src="https://code.jquery.com/jquery-3.7.1.min.js"></script>
  <script>
    (function () {
      var lines = [];
      $.Deferred()
        .resolve({ id: 0 })
        .then(function (data) {
          if (!data.id) {
            throw new Error("Invalid user id");
          }
          lines.push("then: valid id " + data.id);
        })
        .catch(function (err) {
          lines.push("catch: " + err.message);
        });

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

Lines: 0 | Characters: 0

Live Preview Auto-refresh on Run

jQuery deferred.catch() — thrown error in then() (Try It)