<form><input type='file' id="poem" accept='text/plain' onchange='printPoem(event)' ></form>

        <script>
        if (filename !== null){
        document.getElementById("getfilename").innerHTML = filename;
        //document.write(filename);
         }
        </script>

function printPoem(event) {
            var input = event.target;
            var reader = new FileReader();
            reader.onload = function(){
              var text = reader.result;
              //document.write(reader.result.substring(0, 200));
              var fullPath = document.getElementById("poem").value;

              if (fullPath) {
                var startIndex = (fullPath.indexOf('\') >= 0 ?
                          fullPath.lastIndexOf('\') : fullPath.lastIndexOf('/'));
                filename = fullPath.substring(startIndex);
                if (filename.indexOf('\') === 0 || filename.indexOf('/') === 0) {
                    filename = filename.substring(1);
                }
                //alert(filename);
            }
                document.getElementById("displayPoem").innerHTML = text;
            };
            reader.readAsText(input.files[0]);
            return(filename);

<input type="button"  class="button" value="Visualize" onclick="window.location.href='visualization.html'">