Officeoff.ru,
<!DOCTYPE HTML>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
</head>
<body>
<input name="" type="button" value="test" onclick="alert(this.closest)">
<input name="" type="button" value="test" onclick="alert(this.closest)">
</body>
</html>