how to open javascript file

1function readSingleFile(e) {
2  var file = e.target.files[0];
3  if (!file) {
4    return;
5  }
6  var reader = new FileReader();
7  reader.onload = function(e) {
8    var contents = e.target.result;
9    displayContents(contents);
10  };
11  reader.readAsText(file);
12}
13
14function displayContents(contents) {
15  var element = document.getElementById('file-content');
16  element.textContent = contents;
17}
18
19document.getElementById('file-input')
20  .addEventListener('change', readSingleFile, false);

1window.open("file:///D:/Hello.txt");

1// you can open JavaScript files (.js) in any text editor