DOMTokenList.keys()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

DOMTokenList keys() 方法返回一个iterator, 可以用来遍历这个对象中的所有的键,键的类型是无符号整型

语法

tokenList.keys();

参数

无。

返回值

返回一个 iterator.

示例

在下面的例子中,我们获取了一个使用 Element.classList属性获取了一个 DOMTokenList ,在这里它表示了这个 <span> 元素的所有 class 属性值的键(索引)。然后我们使用了它的 keys()方法获取了一个 iterator,最后再使用 for ... of 循环来对所有键(这里是索引)进行遍历,将遍历的每一个结果都写到这个 <span> 标签内(使用Node.textContent属性)显示。

首先,例子使用的 HTML 代码为:

html
<span class="a b c"></span>

这是 JavaScript 代码:

js
var span = document.querySelector("span");
var classes = span.classList;
var iterator = classes.keys();

for (var value of iterator) {
  span.textContent += value + " ++ ";
}

输出为:

规范

No specification found

No specification data found for api.DOMTokenList.keys.
Check for problems with this page or contribute a missing spec_url to mdn/browser-compat-data. Also make sure the specification is included in w3c/browser-specs.

浏览器兼容性

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desktopmobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
keys

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Full support
Full support