The .after() and .insertAfter() methods perform the same task. The major difference is in the syntax—specifically, in the placement of the content and target. With .after(), the selector expression preceding the method is the container after which the content is inserted. With .insertAfter(), on the other hand, the content precedes the method, either as a selector expression or as markup created on the fly, and it is inserted after the target container.

Using the following HTML:

<div class="container">
  <h2>Greetings</h2>
  <div class="inner">Hello</div>
  <div class="inner">Goodbye</div>
</div>

Content can be created and then inserted after several elements at once:

$('.inner').after('<p>Test</p>');

Each inner <div> element gets this new content:

<div class="container">
  <h2>Greetings</h2>
  <div class="inner">Hello</div>
  <p>Test</p>
  <div class="inner">Goodbye</div>
  <p>Test</p>
</div>

An element in the DOM can also be selected and inserted after another element:

$('.container').after($('h2'));

If an element selected this way is inserted elsewhere, it will be moved rather than cloned:

<div class="container">
  <div class="inner">Hello</div>
  <div class="inner">Goodbye</div>
</div>
<h2>Greetings</h2>

If there is more than one target element, however, cloned copies of the inserted element will be created for each target after the first.

Inserting Disconnected DOM nodes

As of jQuery 1.4, .before() and .after() will also work on disconnected DOM nodes. For example, given the following code:

$('<div/>').after('<p></p>');

The result is a jQuery set containing a div and a paragraph, in that order. That set can be further manipulated, even before it is inserted in the document.

$('<div/>').after('<p></p>').addClass('foo')
  .filter('p').attr('id', 'bar').html('hello')
.end()
.appendTo('body');

This results in the following elements inserted just before the closing </body> tag:

<div class="foo"></div>
<p class="foo" id="bar">hello</p>

Passing a Function

As of jQuery 1.4, .after() supports passing a function that returns the elements to insert.

$('p').after(function() {
  return '<div>' + this.className + '</div>';
});

This example inserts a <div> after each paragraph, with each new <div> containing the class name(s) of its preceding paragraph.

Additional Arguments

Similar to other content-adding methods such as .prepend() and .before(), .after() also supports passing in multiple arguments as input. Supported input includes DOM elements, jQuery objects, HTML strings, and arrays of DOM elements.

For example, the following will insert two new <div>s and an existing <div> after the first paragraph:

var $newdiv1 = $('<div id="object1"/>'),
    newdiv2 = document.createElement('div'),
    existingdiv1 = document.getElementById('foo');

$('p').first().after($newdiv1, [newdiv2, existingdiv1]);

Since .after() can accept any number of additional arguments, the same result can be achieved by passing in the three <div>s as three separate arguments, like so: $('p').first().after($newdiv1, newdiv2, existingdiv1). The type and number of arguments will largely depend on the elements are collected in the code.