DocumentFragment

The DocumentFragment interface represents a minimal document object that has no parent.

It is used as a lightweight version of {{domxref("Document")}} that stores a segment of a document structure comprised of nodes just like a standard document. The key difference is due to the fact that the document fragment isn't part of the active document tree structure. Changes made to the fragment don't affect the document.

Constructor

{{ domxref("DocumentFragment.DocumentFragment()", "DocumentFragment()") }}
- : Creates and returns a new DocumentFragment object.

Instance properties

This interface has no specific properties, but inherits those of its parent, {{domxref("Node")}}.

{{ domxref("DocumentFragment.childElementCount") }} {{ReadOnlyInline}}
- : Returns the amount of child {{domxref("Element","elements")}} the DocumentFragment has.
{{ domxref("DocumentFragment.children") }} {{ReadOnlyInline}}
- : Returns a live {{domxref("HTMLCollection")}} containing all objects of type {{domxref("Element")}} that are children of the DocumentFragment object.
{{ domxref("DocumentFragment.firstElementChild") }} {{ReadOnlyInline}}
- : Returns the {{domxref("Element")}} that is the first child of the DocumentFragment object, or null if there is none.
{{ domxref("DocumentFragment.lastElementChild") }} {{ReadOnlyInline}}
- : Returns the {{domxref("Element")}} that is the last child of the DocumentFragment object, or null if there is none.

Instance methods

This interface inherits the methods of its parent, {{domxref("Node")}}.

{{DOMxRef("DocumentFragment.append()")}}
- : Inserts a set of {{domxref("Node")}} objects or strings after the last child of the document fragment.
{{DOMxRef("DocumentFragment.prepend()")}}
- : Inserts a set of {{domxref("Node")}} objects or strings before the first child of the document fragment.
{{domxref("DocumentFragment.querySelector()")}}
- : Returns the first {{domxref("Element")}} node within the DocumentFragment, in document order, that matches the specified selectors.
{{domxref("DocumentFragment.querySelectorAll()")}}
- : Returns a {{domxref("NodeList")}} of all the {{domxref("Element")}} nodes within the DocumentFragment that match the specified selectors.
{{DOMxRef("DocumentFragment.moveBefore()")}}
- : Moves a given {{domxref("Node")}} inside the invoking DocumentFragment as a direct child, before a given reference node, without removing and then inserting the node.
{{DOMxRef("DocumentFragment.replaceChildren()")}}
- : Replaces the existing children of a DocumentFragment with a specified new set of children.
{{domxref("DocumentFragment.getElementById()")}}
- : Returns the first {{domxref("Element")}} node within the DocumentFragment, in document order, that matches the specified ID. Functionally equivalent to {{domxref("Document.getElementById()")}}.

Usage notes

A common use for DocumentFragment is to create one, assemble a DOM subtree within it, then append or insert the fragment into the DOM using {{domxref("Node")}} interface methods such as {{domxref("Node.appendChild", "appendChild()")}}, {{domxref("Element.append", "append()")}}, or {{domxref("Node.insertBefore", "insertBefore()")}}. Doing this moves the fragment's nodes into the DOM, leaving behind an empty DocumentFragment.

This interface is also of great use with Web components: {{HTMLElement("template")}} elements contain a DocumentFragment in their {{domxref("HTMLTemplateElement.content")}} property.

An empty DocumentFragment can be created using the {{domxref("document.createDocumentFragment()")}} method or the constructor.

Performance

The performance benefit of DocumentFragment is often overstated. In fact, in some engines, using a DocumentFragment is slower than appending to the document in a loop as demonstrated in this benchmark. However, the difference between these examples is so marginal that it's better to optimize for readability than performance.

Example

HTML

html

<ul></ul>

JavaScript

const ul = document.querySelector("ul");
const fruits = ["Apple", "Orange", "Banana", "Melon"];

const fragment = new DocumentFragment();

for (const fruit of fruits) {
  const li = document.createElement("li");
  li.textContent = fruit;
  fragment.append(li);
}

ul.append(fragment);