jQuery ajax callback with loader

loader.js

// setup a loading dialog
function showLoader() {
  $('body').append('<div id="dialog-loading"></div>');
  $("#dialog-loading").dialog({
    height: 35,
    draggable: false,
    resizable: false,
    modal: true
  });

  $('span#ui-dialog-title-dialog-loading').after('<img src="' + basePath + 'images/ajax-loader-bar.gif" id="loader" />');
  $('#dialog-loading').parent('.ui-widget-content').css("background", "none");
  $('#dialog-loading').parent('.ui-widget-content').css("border", "none");
}

// remove loading dialog after success
function removeLoader() {
  $('#dialog-loading').dialog("close");
  $('#dialog-loading').remove();
}


$(document).ready(function () {
  $('button#update').change(function () {
    showLoader();
    var id = $('input').val();
    $.ajax({
      url: 'path/to/action/' + id,
      type: "POST",
      traditional: true,
      data: { 'id': id },
      success: function (html) {
        removeLoader();
        $('div').html($(html));
      }
    });
 });
});