Node.insertBefore

Summary

Inserts the specified node before a reference element as a child of the current node.

Syntax

var insertedElement = parentElement.insertBefore(newElement, referenceElement);

If referenceElement is null, or undefinednewElement is inserted at the end of the list of child nodes.

  • insertedElement The node being inserted, that is newElement
  • parentElement The parent of the newly inserted node.
  • newElement The node to insert.
  • referenceElement The node before which newElement is inserted.

Example

<div id="parentElement">
  <span id="childElement">foo bar</span>
</div>

<script>
// Create a new, plain <span> element
var sp1 = document.createElement("span");

// Get a reference to the element, before we want to insert the element
var sp2 = document.getElementById("childElement");
// Get a reference to the parent element
var parentDiv = sp2.parentNode;

// Insert the new element into the DOM before sp2
parentDiv.insertBefore(sp1, sp2);
</script>

There is no insertAfter method. It can be emulated by combining the insertBefore method with nextSibling.

In the previous example, sp1 could be inserted after sp2 using:

parentDiv.insertBefore(sp1, sp2.nextSibling);

If sp2 does not have a next sibling, then it must be the last child — sp2.nextSibling returns null, and sp1 is inserted at the end of the child node list (immediately after sp2).

In Internet Explorer an undefined value as referenceElement will throw errors, while in rest of the modern browsers, this works fine.

Example 2

Insert an element before the first child element, using the firstChild property.

// Get a reference to the element in which we want to insert a new node
var parentElement = document.getElementById('parentElement');
// Get a reference to the first child
var theFirstChild = parentElement.firstChild;

// Create a new element
var newElement = document.createElement("div");

// Insert the new element before the first child
parentElement.insertBefore(newElement, theFirstChild);

When the element does not have a first child, then firstChild is null. The element is still appended to the parent, after the last child. Since the parent element did not have a first child, it did not have a last child either. Consequently, the new element is the only element, after insertion.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 1.0 (Yes) (Yes) (Yes) (Yes)
Feature Android Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support ? ? ? ? ?

Specification

Document Tags and Contributors

Last updated by: deveedutta,