使用 querySelectorAll().方法返回的结果是否有序?
- 作者: 吕夫斯基
- 来源: 51数据库
- 2022-10-20
问题描述
我正在尝试制作一个适用于多个页面的 js 代码.我正在尝试使用 querySelectorAll() 从 DOM 中获取元素.
I'm trying to make a js code that works with multiple pages. I'm trying to use querySelectorAll() to obtain the elements form the DOM.
我需要订购元素.为此，我可以使用 xPath 或选择器(我更喜欢使用选择器，但 xPath 也可以).问题是:
querySelectorAll() 返回的 NodeList 中的元素是否按照标签在 HTML 中出现的顺序排列?
I need the elements to be ordered. In order to do that I may use xPath or selectors (I'd prefer to use selectors but xPath is also ok). The problem is:
Are the elements in the NodeList returned by querySelectorAll() ordered against the order that the tags appear in the HTML?
注意:我想添加标签:querySelectorAll
Note: I'd like to add the tag: querySelectorAll
推荐答案
返回的节点列表是有序的.快速测试证明了这一点:
The returned node list is ordered. A quick test proved it:
document.querySelectorAll("body, head")[0]; //Returned [object HTMLHeadElement]
显然，<head> 标签出现在 HTML 文档中的 <body> 之前.NodeList 的第一个元素也是 <head> 元素，即使选择器在 `head 之前显示 body.
Obviously, the <head> tag appears before <body> in a HTML document. The first element of the NodeList is also a <head> element, even if the selector shows body before `head.
来自 http://www.w3.org/TR/selectors-api/#queryselectorall:
NodeSelector 接口上的 querySelectorAll() 方法必须，当调用，返回一个包含所有匹配元素的 NodeList节点子树中的节点，按文档顺序.如果没有此类节点，该方法必须返回一个空的 NodeList.
The querySelectorAll() method on the NodeSelector interface must, when invoked, return a NodeList containing all of the matching Element nodes within the node’s subtrees, in document order. If there are no such nodes, the method must return an empty NodeList.
