如何使用 jQuery 选择单个子元素?

发布于 2024-08-06 04:56:12 字数 370 浏览 4 评论 0原文

使用 jQuery 如何选择单个子元素?我查看了 Traversing API,知道我可以像这样选择所有直接子 img 元素:

$(this).children('img');

并且要选择第一个子 img 元素,我可以使用下标,例如这个:

$(this).children('img')[0];

但我想我有点惊讶我不能这样做:

$(this).child('img'); // no subscript, returns single element

或者我错过了什么?

Using jQuery how do I select a single child element? I've looked at the Traversing API and know I can select all the immediate children img elements like this:

$(this).children('img');

And to select the first child img element I could use a subscript like this:

$(this).children('img')[0];

But I guess I'm kind of surprised I can't do this:

$(this).child('img'); // no subscript, returns single element

Or have I missed something?

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评论(6

善良天后 2024-08-13 04:56:12

我认为你想要做的是这样的:

$(this).children('img').eq(0);

这会给你一个包含第一个 img 元素的 jquery 对象,而

$(this).children('img')[0];

会给你 img 元素本身。

I think what you want to do is this:

$(this).children('img').eq(0);

this will give you a jquery object containing the first img element, whereas

$(this).children('img')[0];

will give you the img element itself.

<逆流佳人身旁 2024-08-13 04:56:12

不会。每个 jQuery 函数都会返回一个 jQuery 对象,这就是它的工作原理。这是 jQuery 魔力的关键部分。

如果你想访问底层元素,你有三个选择...

  1. 不要使用 jQuery
  2. 使用 [0] 来引用它
  3. 扩展 jQuery 来做你想做的事情...

    $.fn.child = 函数 {
        返回$(this).children(s)[0];
    }
    

No. Every jQuery function returns a jQuery object, and that is how it works. This is a crucial part of jQuery's magic.

If you want to access the underlying element, you have three options...

  1. Do not use jQuery
  2. Use [0] to reference it
  3. Extend jQuery to do what you want...

    $.fn.child = function(s) {
        return $(this).children(s)[0];
    }
    
泼猴你往哪里跑 2024-08-13 04:56:12

也许是这样?

$('img', this)[0]

Maybe in this way?

$('img', this)[0]
半枫 2024-08-13 04:56:12

您可以仅使用带有 jQ​​uery 的 CSS 选择器来定位第一个子元素:

$(this).children('img:nth-child(1)');

如果您想定位第二个子元素,只需将 1 更改为 2:

$(this).children('img:nth-child(2)');

依此类推。

如果您想定位更多元素,您可以使用 for 循环:

for (i = 1; i <= $(this).children().length; i++) {
    let childImg =  $(this).children("img:nth-child("+ i +")");
    // Do stuff...
}

You can target the first child element with just using CSS selector with jQuery:

$(this).children('img:nth-child(1)');

If you want to target the second child element just change 1 to 2:

$(this).children('img:nth-child(2)');

and so on..

if you want to target more elements, you can use a for loop:

for (i = 1; i <= $(this).children().length; i++) {
    let childImg =  $(this).children("img:nth-child("+ i +")");
    // Do stuff...
}
ヅ她的身影、若隐若现 2024-08-13 04:56:12

不是问题所要求的 jQuery,而是本机(即不需要库)我认为更好的工具是 querySelector 来获取选择器的单个实例:

let el = document.querySelector('img');
console.log(el);

对于所有匹配实例,请使用 document.querySelectorAll(),或者对于另一个元素中的实例,您可以按如下方式链接:

// Get some wrapper, with class="parentClassName"
let parentEl = document.querySelector('.parentClassName');
// Get all img tags within the parent element by parentEl variable
let childrenEls = parentEl.querySelectorAll('img');

请注意,以上等效于:

let childrenEls = document.querySelector('.parentClassName').querySelectorAll('img');

Not jQuery, as the question asks for, but natively (i.e., no libraries required) I think the better tool for the job is querySelector to get a single instance of a selector:

let el = document.querySelector('img');
console.log(el);

For all matching instances, use document.querySelectorAll(), or for those within another element you can chain as follows:

// Get some wrapper, with class="parentClassName"
let parentEl = document.querySelector('.parentClassName');
// Get all img tags within the parent element by parentEl variable
let childrenEls = parentEl.querySelectorAll('img');

Note the above is equivalent to:

let childrenEls = document.querySelector('.parentClassName').querySelectorAll('img');
血之狂魔 2024-08-13 04:56:12
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