Difference Between jQuery append() and appendTo()

While both the jQuery append() and appendTo() methods perform the same functional task of inserting specified content at the end of a targeted DOM element, their primary difference lies in their syntax, the order of target versus content, and how they handle method chaining. Understanding which element is returned by each method determines whether subsequent operations affect the parent container or the newly injected content.

Syntax and Parameter Order

The most apparent difference between the two methods is the inverted syntax used to define the target container and the content being appended.

append() Syntax: $(target).append(content)
With append(), you select the target container first, and the content to be inserted is passed as an argument. The content can be an HTML string, a DOM element, a text node, an array, or another jQuery object.
appendTo() Syntax: $(content).appendTo(target)
With appendTo(), you select or create the content first, and the target container is passed as the argument. The target can be a selector expression, a DOM element, or a jQuery object.

Code Comparison

Consider the following HTML structure:

<div class="container"></div>

To insert a paragraph inside the div using append():

$('.container').append('<p>Hello World</p>');

To achieve the exact same DOM result using appendTo():

$('<p>Hello World</p>').appendTo('.container');

In both instances, the resulting HTML is:

<div class="container">
  <p>Hello World</p>
</div>

Method Chaining and Return Values

The critical functional difference arises during jQuery method chaining. A jQuery method typically returns the jQuery object it was called on, which dictates what subsequent chained methods will manipulate.

append() returns the target element.
Because append() operates on the parent container, chaining another method will apply styles, attributes, or event listeners to that parent container.
```
$('.container')
 .append('Hello World')
 .css('border', '1px solid black'); 
// The border is applied to the .container element.
```
appendTo() returns the appended content.
Because appendTo() operates on the child content, chaining another method will apply changes directly to the newly inserted element.
```
$('Hello World')
 .appendTo('.container')
 .css('color', 'red'); 
// The red text color is applied to the element, not the container.
```

When to Use Each Method

Choose append() when your primary focus is on the container element, such as when you need to inject multiple items sequentially into a list or continue styling and configuring the wrapper element.

Choose appendTo() when you dynamically create a new element and immediately need to attach event handlers, add classes, or apply styles to that specific new element before or after placing it in the DOM.