Node: firstChild property

The read-only firstChild property of the Node interface returns the node's first child in the tree, or null if the node has no children.

If the node is a Document, this property returns the first node in the list of its direct children.

Note: This property returns any type of node that is the first child of this one. It may be a Text or a Comment node. If you want to get the first Element that is a child of another element, consider using Element.firstElementChild.

Value

A Node, or null if there are none.

Example

This example demonstrates the use of firstChild and how whitespace nodes might interfere with using this property. 

<p id="para-01">
  <span>First span</span>
</p>

<script>
  const p01 = document.getElementById("para-01");
  console.log(p01.firstChild.nodeName);
</script>

In the above, the console will show '#text' because a text node is inserted to maintain the whitespace between the end of the opening <p> and <span> tags. Any whitespace will create a #text node, from a single space to multiple spaces, returns, tabs, and so on.

Another #text node is inserted between the closing </span> and </p> tags.

If this whitespace is removed from the source, the #text nodes are not inserted and the span element becomes the paragraph's first child. 

<p id="para-01"><span>First span</span></p>

<script>
  const p01 = document.getElementById("para-01");
  console.log(p01.firstChild.nodeName);
</script>

Now the console will show 'SPAN'.

To avoid the issue with node.firstChild returning #text or #comment nodes, Element.firstElementChild can be used to return only the first element node.

Specifications

Specification
DOM Standard
# ref-for-dom-node-firstchild①

Browser compatibility

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See also