DocumentFragment - Web APIs | MDN (original) (raw)
Baseline
Widely available *
The DocumentFragment interface represents a minimal document object that has no parent.
It is used as a lightweight version of 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.
EventTarget Node DocumentFragment
Constructor
Creates and returns a new DocumentFragment object.
Instance properties
This interface has no specific properties, but inherits those of its parent, Node.
DocumentFragment.childElementCount Read only
Returns the amount of child elements the DocumentFragment has.
DocumentFragment.children Read only
Returns a live HTMLCollection containing all objects of type Element that are children of the DocumentFragment object.
DocumentFragment.firstElementChild Read only
Returns the Element that is the first child of the DocumentFragment object, or null if there is none.
DocumentFragment.lastElementChild Read only
Returns the 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, Node.
Inserts a set of Node objects or strings after the last child of the document fragment.
Inserts a set of Node objects or strings before the first child of the document fragment.
DocumentFragment.querySelector()
Returns the first Element node within the DocumentFragment, in document order, that matches the specified selectors.
DocumentFragment.querySelectorAll()
Returns a NodeList of all the Element nodes within the DocumentFragment that match the specified selectors.
DocumentFragment.moveBefore() Experimental
Moves a given Node inside the invoking DocumentFragment as a direct child, before a given reference node, without removing and then inserting the node.
DocumentFragment.replaceChildren()
Replaces the existing children of a DocumentFragment with a specified new set of children.
DocumentFragment.getElementById()
Returns the first Element node within the DocumentFragment, in document order, that matches the specified ID. Functionally equivalent to 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 Node interface methods such as appendChild(), append(), or 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: elements contain a DocumentFragment in their HTMLTemplateElement.content property.
An empty DocumentFragment can be created using the 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
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);
Result
Specifications
| Specification |
|---|
| DOM # interface-documentfragment |