Web/API/ChildNode/before

The ChildNode.before() method inserts a set of Node or DOMString objects in the children list of this ChildNode's parent, just before this ChildNode. DOMString objects are inserted as equivalent Text nodes.

Syntax

[Throws, Unscopable] 
void ChildNode.before((Node or DOMString)... nodes);

Parameters

nodes

A set of Node or DOMString objects to insert.

Exceptions

• HierarchyRequestError: Node cannot be inserted at the specified point in the hierarchy.

Examples

Inserting an element

var parent = document.createElement("div");
var child = document.createElement("p");
parent.appendChild(child);
var span = document.createElement("span");

child.before(span);

console.log(parent.outerHTML);
// "<div><span></span><p></p></div>"

Inserting text

var parent = document.createElement("div");
var child = document.createElement("p"); 
parent.appendChild(child);

child.before("Text"); 

console.log(parent.outerHTML);
// "<div>Text<p></p></div>"

Inserting an element and text

var parent = document.createElement("div");
var child = document.createElement("p"); 
parent.appendChild(child); 
var span = document.createElement("span");

child.before(span, "Text"); 

console.log(parent.outerHTML);
// "<div><span></span>Text<p></p></div>"

ChildNode.before() is unscopable

The before() method is not scoped into the with statement. See Symbol.unscopables for more information.

with(node) { 
  before("foo");
}
// ReferenceError: before is not defined

Polyfill

You can polyfill the before() method in Internet Explorer 9 and higher with the following code:

// from: https://github.com/jserz/js_piece/blob/master/DOM/ChildNode/before()/before().md
(function (arr) {
  arr.forEach(function (item) {
    if (item.hasOwnProperty('before')) {
      return;
    }
    Object.defineProperty(item, 'before', {
      configurable: true,
      enumerable: true,
      writable: true,
      value: function before() {
        var argArr = Array.prototype.slice.call(arguments),
          docFrag = document.createDocumentFragment();
        
        argArr.forEach(function (argItem) {
          var isNode = argItem instanceof Node;
          docFrag.appendChild(isNode ? argItem : document.createTextNode(String(argItem)));
        });
        
        this.parentNode.insertBefore(docFrag, this);
      }
    });
  });
})([Element.prototype, CharacterData.prototype, DocumentType.prototype]);

Specification

Specification	Status	Comment
DOMThe definition of 'ChildNode.before()' in that specification.	Living Standard	Initial definition.

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
before Experimental'	Chrome Full support 54	Edge Full support 17	Firefox Full support 49	IE No support No	Opera Full support 39	Safari Full support 10	WebView Android Full support 54	Chrome Android Full support 54	Firefox Android Full support 49	Opera Android Full support 41	Safari iOS Full support 10	Samsung Internet Android Full support 6.0

Legend

Full support  

Full support

No support  

No support

Experimental. Expect behavior to change in the future.'

Experimental. Expect behavior to change in the future.

See also

• ChildNode and ParentNode
• ChildNode.after()
• ParentNode.append()
• Node.appendChild()
• Node.insertBefore()
• Element.insertAdjacentElement()
• NodeList

ChildNode.before() by Mozilla Contributors is licensed under CC-BY-SA 2.5.