From 9daad59fa2578dcc9603833b0a9a22b93d362b5e Mon Sep 17 00:00:00 2001 From: MDN Date: Fri, 16 Apr 2021 00:10:51 +0000 Subject: [CRON] sync translated content --- .../api/parentnode/firstelementchild/index.html | 96 ++++++++++++++++++++++ 1 file changed, 96 insertions(+) create mode 100644 files/zh-tw/orphaned/web/api/parentnode/firstelementchild/index.html (limited to 'files/zh-tw/orphaned') diff --git a/files/zh-tw/orphaned/web/api/parentnode/firstelementchild/index.html b/files/zh-tw/orphaned/web/api/parentnode/firstelementchild/index.html new file mode 100644 index 0000000000..ca33d60793 --- /dev/null +++ b/files/zh-tw/orphaned/web/api/parentnode/firstelementchild/index.html @@ -0,0 +1,96 @@ +--- +title: ParentNode.firstElementChild +slug: orphaned/Web/API/ParentNode/firstElementChild +translation_of: Web/API/ParentNode/firstElementChild +original_slug: Web/API/ParentNode/firstElementChild +--- +

{{ APIRef("DOM") }}

+ +

ParentNode.firstElementChild 介面會會返回 ParentNode的第一個子元素(唯讀) ,如果該節點沒有子節點則返回null

+ +
+

This property was initially defined in the {{domxref("ElementTraversal")}} pure interface. As this interface contained two distinct set of properties, one aimed at {{domxref("Node")}} that have children, one at those that are children, they have been moved into two separate pure interfaces, {{domxref("ParentNode")}} and {{domxref("ChildNode")}}. In this case, firstElementChild moved to {{domxref("ParentNode")}}. This is a fairly technical change that shouldn't affect compatibility.

+
+ +

語法

+ +
var element = node.firstElementChild;
+
+ +

範例

+ +
<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>
+
+ +

適用於IE8, IE9 和 Safari的Polyfill

+ +
// Overwrites native 'firstElementChild' prototype.
+// Adds Document & DocumentFragment support for IE9 & Safari.
+;(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);
+
+ +

規範

+ + + + + + + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('DOM WHATWG', '#dom-parentnode-firstelementchild', 'ParentNode.firstElementChild')}}{{Spec2('DOM WHATWG')}}Split the ElementTraversal interface in {{domxref("ChildNode")}} and ParentNode. This method is now defined on the latter.
+ The {{domxref("Document")}} and {{domxref("DocumentFragment")}} implemented the new interfaces.
{{SpecName('Element Traversal', '#attribute-firstElementChild', 'ElementTraversal.firstElementChild')}}{{Spec2('Element Traversal')}}Added its initial definition to the ElementTraversal pure interface and use it on {{domxref("Element")}}.
+ +

瀏覽器相容性

+ + + +

{{Compat("api.ParentNode.firstElementChild")}}

+ +

參見

+ + -- cgit v1.2.3-54-g00ecf