convert.html

<script>
var openFile = function(event) {
  var input = event.target;

  var reader = new FileReader();
  reader.onload = function() {
    var text = reader.result;
    var node = document.getElementById('output');
	var bruh = '';
	reader.result.split('').forEach((e)=>{
		bruh += e.charCodeAt(0).toString(16).padStart(2, '0').toUpperCase();
	});
    <!-- node.innerText = bruh; -->
	
	var link = document.createElement('a');
	var file = new Blob([bruh], { type: 'text/plain' });
	link.href = URL.createObjectURL(file);
	link.download = input.files[0].name + '.txt';
	link.click();
	URL.revokeObjectURL(link.href);
	

	
  };
  reader.readAsBinaryString(input.files[0]);
};
</script>
<input type='file' onchange='openFile(event)'><br>
<!-- <textarea id='output'> -->

<!-- </textarea> -->