html/forms/file-examples/simple-file.html

<!DOCTYPE html>
<html lang="en-US">
  <head>
    <title>File upload example</title>
    <style>
      div {
        margin-bottom: 10px;
      }
    </style>
  </head>
  <body>
      <form>
       <div>
         <label for="file">Choose file to upload</label>
         <input type="file" id="file" name="file" multiple>
       </div>
       <div>
         <button>Submit</button>
       </div>
      </form>
     <script>
       var test = document.querySelector('input');
     </script>
  </body>
</html>