Element.firstElementChild

ParentNode.firstElementChild 只读属性，返回对象的第一个孩子 Element, 如果没有子元素，则为null。

语法

var element = node.firstElementChild;

var childNode = elementNodeReference.firstElementChild; 

例子

<ul id="foo">
  <li>First  (1)</li>
  <li>Second (2)</li>
  <li>Third  (3)</li>
</ul>

<script>
var foo = document.getElementById('foo');
// yields: First  (1)
console.log(foo.firstElementChild.textContent);
</script>

Polyfill for IE8, IE9 and Safari

// Overwrites native 'firstElementChild' prototype.
// Adds Document & DocumentFragment support for IE9 & Safari.
// Returns array instead of HTMLCollection.
;(function(constructor) {
    if (constructor &&
        constructor.prototype &&
        constructor.prototype.firstElementChild == null) {
        Object.defineProperty(constructor.prototype, 'firstElementChild', {
            get: function() {
                var node, nodes = this.childNodes, i = 0;
                while (node = nodes[i++]) {
                    if (node.nodeType === 1) {
                        return node;
                    }
                }
                return null;
            }
        });
    }
})(window.Node || window.Element);

规范

浏览器兼容性

相关链接

• The ParentNode and ChildNode pure interfaces.
• Object types implementing this pure interface: Document, Element, and DocumentFragment.