IPhone8 phone does not respond to formData operation, why?

nothing pops up on the iPhone8 phone. Why? 

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>
<body>
  <button id="btn">click me</button>
  <script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.min.js"></script>
  <script>
    $("-sharpbtn").on("click", function() {
      var formdata = new FormData();
      formdata.set("key", "value");
      alert(formdata.get("key"));
    });
  </script>
</body>
</html>
Javascript html5
Mar.18,2021

have you tried other phones?

safari does not allow users to alert
you can try to put a button click after alert

write in a click event to see the pop-up

Sunian, have you solved the problem? I'm also stuck in this

some iPhones have only one append method for sessionStorage, no get and no set, but can only append and submit directly

.

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MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b30ae1-2aa79.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b30ae1-2aa79.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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