onsubmit event not working if in the form is a input with confirm name

onsubmit event not working if in the form is a input with confirm name or id .

if i add below input to the form the onsubmit event not working

 <input type="checkbox" name="confirm" id="confirm">

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
<form action="/" method="post" onsubmit="return confirm('Are you sure ?')">
    <input type="text" name="name">
    <br>
    <input type="checkbox" name="confirm" id="confirm">
    <button type="submit">submit</button>
</form>
</body>
</html>

when i removed the input with confirm name the onsubmit event work!!!