W3cubDocs

TreeWalker: firstChild() method

The TreeWalker.firstChild() method moves the current Node to the first visible child of the current node, and returns the found child. If no such child exists, it returns null and the current node is not changed.

Syntax

firstChild()

Parameters

None.

Return value

A Node object or null.

Examples

const treeWalker = document.createTreeWalker(
  document.body,
  NodeFilter.SHOW_ELEMENT,
  {
    acceptNode(node) {
      return NodeFilter.FILTER_ACCEPT;
    },
  },
  false,
);
const node = treeWalker.firstChild(); // returns the first child of the root element, or null if none

Specifications

Specification
DOM Standard # dom-treewalker-firstchild

Browser compatibility