Post_3_1.js

function uploadFiles(inputId) {
  var input = document.getElementById(inputId);
  var files = input.files;
  var formData = new FormData();

  for (var i = 0; i != files.length; i++) {
    formData.append("files", files[i]);
  }

  startUpdatingProgressIndicator();
  $.ajax(
    {
      url: "/uploader",
      data: formData,
      processData: false,
      contentType: false,
      type: "POST",
      success: function (data) {
        stopUpdatingProgressIndicator();
        alert("Files Uploaded!");
      }
    }
  );
}

var intervalId;

function startUpdatingProgressIndicator() {
  $("#progress").show();

  intervalId = setInterval(
    function () {
      // We use the POST requests here to avoid caching problems (we could use the GET requests and disable the cache instead)
      $.post(
        "/uploader/progress",
        function (progress) {
          $("#bar").css({ width: progress + "%" });
          $("#label").html(progress + "%");
        }
      );
    },
    10
  );
}

function stopUpdatingProgressIndicator() {
  clearInterval(intervalId);
}