HTMLCollection.length

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.

HTMLCollection.length 属性返回 HTMLCollection 中的元素数量。

值

一个正整数，表示 HTMLCollection 中元素的数量。

示例

length 属性在 DOM 编程中通常很有用。它通常用于测试集合的长度，去看它是否真的存在。它也通常用于 for 循环中的迭代器，如下示例。

js
// All the elements with the class ".test" in the document
var items = document.getElementsByClassName("test");

// For each test item in the list,
// append the entire element as a string of HTML
var gross = "";
for (var i = 0; i < items.length; i++) {
  gross += items[i].innerHTML;
}

// gross is now all the HTML for the test elements

规范

Specification
DOM Standard
# ref-for-dom-htmlcollection-length①

浏览器兼容性

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