CharacterData: before() method

The before() method of the CharacterData interface inserts a set of Node objects and strings in the children list of the CharacterData’s parent, just before the CharacterData node.

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

Syntax

before(...nodes)

Parameters

• nodes
  • : A set of Node objects or strings to insert.

Return value

None (undefined).

Exceptions

• HierarchyRequestError DOMException
  • : 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 this CharacterData node.
    • If one of the added node is not a DocumentFragment, a DocumentType, an Element, or a CharacterData.
    • If this CharacterData node is actually a Text node, and its parent is a Document.
    • If the parent of this CharacterData node is a Document and one of the nodes to insert is a DocumentFragment with more than one Element child, or that has a Text child.

Examples

The before() method allows you to insert new nodes before a CharacterData 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

• appendData()
• after()
• before()
• before()
• append()
• appendChild()
• insertAdjacentElement()