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
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 |
---|---|---|
DOM The 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.
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
before | 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.