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 alert 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
Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|---|
Basic support | 1.0 | 20 (12.10240) | 1.0 (1.7 or earlier) | (Yes) | (Yes) | (Yes) |
Feature | Android | Chrome for Android | Edge | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|---|
Basic support | (Yes) | 1.0 | 20 (12.10240) | 1.0 (1.0) | (Yes) | (Yes) | (Yes) |