HTML Code

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>buttons — check</title>
</head>
<body>
  <p>Press mouse buttons (try combinations).</p>
  <pre id="out">Waiting…</pre>
  <script>
    document.addEventListener("mousedown", function (e) {
      document.getElementById("out").textContent = JSON.stringify({
        left: (e.buttons & 1) === 1,
        right: (e.buttons & 2) === 2,
        middle: (e.buttons & 4) === 4,
        raw: e.buttons
      }, null, 2);
    });
    document.addEventListener("contextmenu", function (e) {
      e.preventDefault();
    });
  </script>
</body>
</html>

Lines: 0 | Characters: 0

Live Preview Auto-refresh on Run

MouseEvent.buttons — bit checks (Try It)