HTML Code

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>blur validate email</title>
  <style>
    body { font-family: sans-serif; padding: 16px; max-width: 360px; }
    label { display: block; margin-bottom: 6px; font-weight: 600; }
    #email { width: 100%; padding: 10px 12px; border: 2px solid #cbd5e1; border-radius: 6px; font-size: 16px; box-sizing: border-box; }
    #email.invalid { border-color: #ef4444; background: #fef2f2; }
    #email-error { color: #dc2626; font-size: 14px; margin-top: 6px; display: none; }
  </style>
</head>
<body>
  <label for="email">Email</label>
  <input type="email" id="email" placeholder="you@example.com">
  <div id="email-error">Please enter a valid email address.</div>
  <script src="https://code.jquery.com/jquery-3.7.1.min.js"></script>
  <script>
    $("#email").on("blur", function() {
      var value = $(this).val().trim();
      var isValid = /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(value);
      $("#email-error").toggle(!isValid && value.length > 0);
      $(this).toggleClass("invalid", !isValid && value.length > 0);
    });
  </script>
</body>
</html>

Lines: 0 | Characters: 0

Live Preview Auto-refresh on Run

jQuery blur event — email validation (Try It)