<script src="https://code.jquery.com/jquery-3.6.0.min.js" integrity="sha256-/xUj+3OJU5yExlq6GSYGSHk7tPXikynS7ogEvDej/m4=" crossorigin="anonymous"></script>
<body>
  <div class="result">ボタンを押してください</div>
  <button class="button1">ボタン1</button>
</body>
$(function() {
  $('.button1').click(function (e) { 
    let alt = e.altKey ? 'ALT+' : '';
    $('.result').text(alt + 'ボタン1が押されました');
  });
});

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External JavaScript

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