“:eq()"之间的区别和.eq() [英] Difference between ":eq()" and .eq()

问题描述

我最近开始学习jQuery.考虑到下面的html结构，我想知道选择器$('ul>li:eq(2)')和$('ul>li').eq(2)之间的基本区别是什么.

I have recently started learning jQuery. Considering follwing html structure, I want to know, what is basic difference between selectors $('ul>li:eq(2)') and $('ul>li').eq(2).

<ul>
    <li>one</li>
    <li>two</li>
    <li>three</li>
    <li>four</li>
    <li>five</li>
</ul>

推荐答案

它们执行相同的操作，但速度明显慢: http://jsperf.com/eq-vs-eq

They do the same thing, but one is significantly slower: http://jsperf.com/eq-vs-eq

:eq()不是CSS伪选择器，它使第一个选择器成为jQuery选择器.因此，它必须由用JavaScript编写的Sizzle选择器库解析.

:eq() is not a CSS pseudo-selector, which makes the first selector a jQuery selector. Therefore, it has to be parsed by the Sizzle selector library, which is written in JavaScript.

第二个是常规CSS选择器，将直接传递到document.querySelectorAll中，它是本地实现的，运行起来会快得多.

The second one is a regular CSS selector and will be passed directly into document.querySelectorAll, which is implemented natively and will end up running much faster.

这篇关于“:eq()"之间的区别和.eq()的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！