没有父级的jQuery子级选择器 [英] jquery child selector without parent

问题描述

我正在看教程中的一些代码，用于创建轮播菜单，并注意到没有父级的父级子级选择器.以前从未见过，并对其实际操作感到困惑.

I was looking at some code from a tutorial for creating a carousel menu and noticed parent child selectors without the parent. Never seen this before, and confused to what it is actually doing.

请参见以下代码:

        var $wrapper = $('> div', this).css('overflow', 'hidden'),
        $slider = $wrapper.find('> ul'),
        $items = $slider.find('> li'),
        $single = $items.filter(':first'),

        singleWidth = $single.outerWidth(), 
        visible = Math.ceil($wrapper.innerWidth() / singleWidth), // note: doesn't include padding or border
        currentPage = 1,
        pages = Math.ceil($items.length / visible);

此处的教程: http://jqueryfordesigners.com/jquery-infinite-carousel/

推荐答案

有一个父项(在本例中为scope)，请注意选择器中的this关键字，该关键字与插件所在的元素有关应用于.

There is a parent(or in this case a scope), notice the this keyword inside the selector, that's relative to the element the plugin is being applied to.

jQuery的选择器允许您设置范围，它可以是任何jQuery元素对象.

jQuery's selectors allow you to set a scope, and it can be any jQuery element object.

考虑

$(".somediv").myplugin();

在插件内部

$("> div", this) 
is actually translated to 
$("> div", $(".somediv"))

看看我的一个问题，答案在很大程度上解释了jQuery的选择器. 在jQuery中选择后代元素最快的方法是什么?

Have a look at one of my questions, the answer explains quite a bit about jQuery's selectors. What is the fastest method for selecting descendant elements in jQuery?

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