The Node.firstChild
read-only
property returns the node's first child in the tree, or null
if the node
has no children. If the node is a Document
, it returns the first
node in the list of its direct children.
Syntax
var childNode = node.firstChild;
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>
var 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>
var 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, ParentNode.firstElementChild
can be used to
return only the first element node. However, node.firstElementChild
requires a shim for Internet Explorer 9 and earlier.
Specifications
Specification | Status | Comment |
---|---|---|
DOM The definition of 'Node.firstChild' in that specification. |
Living Standard | No change |
Document Object Model (DOM) Level 3 Core Specification The definition of 'Node.firstChild' in that specification. |
Obsolete | No change |
Document Object Model (DOM) Level 2 Core Specification The definition of 'Node.firstChild' in that specification. |
Obsolete | No change |
Document Object Model (DOM) Level 1 Specification The definition of 'Node.firstChild' in that specification. |
Obsolete | Initial definition |
Browser compatibility
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