Answers for "why when i read file content i find html txt"

html get text from file

<embed src="file.txt"> // This will show the text contained in file.txt in the page

javascript read file lines into array vanilla

const fileList = event.target.files;
let fileContent = "";

const fr = new FileReader();
fr.onload = () => {
  fileContent = fr.result;
  console.log('Commands', fileContent);
}

fr.readAsText(fileList[0]);