Thebefore() method of theCharacterData interfaceinserts a set ofNode objects and stringsin the children list of theCharacterData's parent, just before theCharacterData node.

Strings are inserted asText nodes; the string is being passed as argument to theText() constructor.

Syntax

before(...nodes)

Parameters

nodes

A set ofNode objects or strings to insert.

Return value

None (undefined).

Exceptions

HierarchyRequestErrorDOMException

Thrown when the new nodes cannot be inserted at the specified point in the hierarchy, that is if one of the following conditions is met:

• If the insertion of one of the added node would lead to a cycle, that is if one of them is an ancestor of thisCharacterData node.
• If one of the added node is not aDocumentFragment, aDocumentType, anElement, or aCharacterData.
• If thisCharacterData node is actually aText node, and its parent is aDocument.
• If the parent of thisCharacterData node is aDocument and one of the nodes to insert is aDocumentFragment with more than oneElement child, or that has aText child.

Examples

Thebefore() method allows you to insert new nodes before aCharacterData node leaving the current node's data unchanged.

const h1TextNode = document.querySelector("h1").firstChild;h1TextNode.before("h1# ");h1TextNode.parentElement.childNodes;// NodeList [#text "h1# ", #text "CharacterData.before()"]h1TextNode.data;// "CharacterData.before()"

Specifications

Browser compatibility

See also

• CharacterData.appendData()
• CharacterData.after()
• DocumentType.before()
• Element.before()
• Element.append()
• Node.appendChild()
• Element.insertAdjacentElement()