在此页

• 特性
• 方法
• 在 JavaScript 中的用法
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

HTMLCollection interface represents a generic collection (array-like object similar to arguments ) of elements (in document order) and offers methods and properties for selecting from the list.

注意： This interface is called HTMLCollection for historical reasons (before the modern DOM, collections implementing this interface could only have HTML elements as their items).

An HTMLCollection in the HTML DOM is live; it is automatically updated when the underlying document is changed.

特性

HTMLCollection.length 只读

Returns the number of items in the collection.

方法

HTMLCollection.item()

Returns the specific node at the given zero-based index into the list. Returns null 若 index 超出范围。

An alternative to accessing collection[ i ] (which instead returns undefined 当 i is out-of-bounds). This is mostly useful for non-JavaScript DOM implementations.

HTMLCollection.namedItem()

Returns the specific node whose ID or, as a fallback, name matches the string specified by 名称 . Matching by name is only done as a last resort, only in HTML, and only if the referenced element supports the 名称 attribute. Returns null if no node exists by the given name.

An alternative to accessing collection[ 名称 ] (which instead returns undefined 当 名称 does not exist). This is mostly useful for non-JavaScript DOM implementations.

在 JavaScript 中的用法

HTMLCollection also exposes its members directly as properties by both name and index. HTML IDs may contain : and . as valid characters, which would necessitate using bracket notation for property access. Currently HTMLCollections does not recognize purely numeric IDs, which would cause conflict with the array-style access, though HTML5 does permit these.

For example, assuming there is one <form> element in the document and its id is myForm :

var elem1, elem2;
// document.forms is an HTMLCollection
elem1 = document.forms[0];
elem2 = document.forms.item(0);
alert(elem1 === elem2); // shows: "true"
elem1 = document.forms.myForm;
elem2 = document.forms.namedItem("myForm");
alert(elem1 === elem2); // shows: "true"
elem1 = document.forms["named.item.with.periods"];
						

规范

规范	状态	注释
DOM The definition of 'HTMLCollection' in that specification.	实时标准

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
HTMLCollection	Chrome 1	Edge 12	Firefox 1	IE 8	Opera 8	Safari 4	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 3.2	Samsung Internet Android 1.0
item	Chrome Yes	Edge 12	Firefox Yes	IE ?	Opera Yes	Safari Yes	WebView Android Yes	Chrome Android Yes	Firefox Android Yes	Opera Android Yes	Safari iOS Yes	Samsung Internet Android Yes
length	Chrome Yes	Edge 12	Firefox Yes	IE ?	Opera Yes	Safari Yes	WebView Android Yes	Chrome Android Yes	Firefox Android Yes	Opera Android Yes	Safari iOS Yes	Samsung Internet Android Yes
namedItem	Chrome Yes	Edge 12	Firefox Yes	IE Yes	Opera Yes	Safari Yes	WebView Android Yes	Chrome Android Yes	Firefox Android Yes	Opera Android Yes	Safari iOS Yes	Samsung Internet Android Yes

图例

完整支持

完整支持

兼容性未知 ?

兼容性未知

另请参阅

• NodeList
• HTMLFormControlsCollection , HTMLOptionsCollection

元数据

• 最后修改： Aug 4, 2020

相关话题

1. DOM (文档对象模型)
2. HTMLCollection
3. 特性

   1. item
4. DOM 相关页面

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   2. AbortSignal
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   4. Attr
   5. ByteString
   6. CDATASection
   7. CSSPrimitiveValue
   8. CSSValue
   9. CSSValueList
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   12. 注释
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   15. DOMError
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