在JavaScript中打开和修改文件的函数

<input type="file" id="fileInput">

<script>
  const fileInput = document.getElementById('fileInput');
  fileInput.addEventListener('change', (event) => {
    const file = event.target.files[0];
    // 在这里可以对文件进行处理
  });
</script>

<input type="file" id="fileInput">

<script>
  const fileInput = document.getElementById('fileInput');
  fileInput.addEventListener('change', (event) => {
    const file = event.target.files[0];
    const reader = new FileReader();
    reader.onload = (e) => {
      const contents = e.target.result;
      // 在这里可以对文件内容进行修改
      const modifiedContents = contents.replace('old', 'new');
      // 将修改后的内容写回文件
      writeFile(file, modifiedContents);
    };
    reader.readAsText(file);
  });

  function writeFile(file, contents) {
    const blob = new Blob([contents], { type: 'text/plain' });
    const url = URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    a.download = file.name;
    a.click();
    URL.revokeObjectURL(url);
  }
</script>