// Back to top
 $('a.top').click(function (e) {
 e.preventDefault();
 $(document.body).animate({scrollTop: 0}, 800);
 });

 <!-- Create an anchor tag -->
 <a class="top" href="#">Back to top</a>

 $.preloadImages = function () {
 for (var i = 0; i < arguments.length; i++) {
  $('<img>').attr('src', arguments[i]);
 }
 };
 
 $.preloadImages('img/hover-on.png', 'img/hover-off.png');

 $('img').load(function () {
 console.log('image load successful');
 });

 $('img').on('error', function () {
 $(this).prop('src', 'img/broken.png');
 });

 $('.btn').hover(function () {
 $(this).addClass('hover');
 }, function () {
 $(this).removeClass('hover');
 });

 $('.btn').hover(function () {
 $(this).toggleClass('hover');
 });

 $('a.no-link').click(function (e) {
 e.preventDefault();
 });

 // Fade
 $('.btn').click(function () {
 $('.element').fadeToggle('slow');
 });
 
 // Toggle
 $('.btn').click(function () {
 $('.element').slideToggle('slow');
 });

 // Close all panels
 $('#accordion').find('.content').hide();
 
 // Accordion
 $('#accordion').find('.accordion-header').click(function () {
 var next = $(this).next();
 next.slideToggle('fast');
 $('.content').not(next).slideUp('fast');
 return false;
 });

 var $columns = $('.column');
 var height = 0;
 $columns.each(function () {
 if ($(this).height() > height) {
  height = $(this).height();
 }
 });
 $columns.height(height);

 var $rows = $('.same-height-columns');
 $rows.each(function () {
 $(this).find('.column').height($(this).height());
 }); 

$('a[href^="http"]').attr('target', '_blank');
$('a[href^="//"]').attr('target', '_blank');
$('a[href^="' + window.location.origin + '"]').attr('target', '_self');

 var search = $('#search').val();
 $('div:not(:contains("' + search + '"))').hide();

 $(document).on('visibilitychange', function (e) {
 if (e.target.visibilityState === "visible") {
  console.log('Tab is now in view!');
 } else if (e.target.visibilityState === "hidden") {
  console.log('Tab is now hidden!');
 }
 });
 

$(document).ajaxError(function (e, xhr, settings, error) {
 console.log(error);
 });

 $('#elem').show();
 $('#elem').html('bla');
 $('#elem').otherStuff();

 $('#elem')
 .show()
 .html('bla')
 .otherStuff();

 var $elem = $('#elem');
 $elem.hide();
 $elem.html('bla');
 $elem.otherStuff();