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如何使用jQuery選擇單個子元素?

[英]How to select a single child element using jQuery?

使用 jQuery 如何選擇單個子元素? 我看過 Traversing API 並且知道我可以像這樣選擇所有直接子元素img元素:

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

要選擇第一個子img元素,我可以使用這樣的下標:

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

但我想我有點驚訝我不能這樣做:

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

或者我錯過了什么?

我想你想做的是這樣的:

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

這將為您提供一個包含第一個 img 元素的 jquery 對象,而

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

會給你 img 元素本身。

不是。每個 jQuery 函數都返回一個 jQuery 對象,這就是它的工作原理。 這是 jQuery 魔法的關鍵部分。

如果你想訪問底層元素,你有三個選擇......

  1. 不要使用 jQuery
  2. 使用[0]來引用它
  3. 擴展 jQuery 來做你想做的事......

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

也許以這種方式?

$('img', this)[0]

不是問題所要求的jQuery ,而是本機(即不需要庫)我認為更好的工作工具是querySelector來獲取選擇器的單個實例:

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

對於所有匹配的實例,請使用document.querySelectorAll() ,或者對於另一個元素中的那些,您可以按如下方式鏈接:

// 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');

注意上面的等價於:

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

您可以僅使用帶有 jQ​​uery 的 CSS 選擇器來定位第一個子元素:

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

如果要定位第二個子元素,只需將 1 更改為 2:

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

等等..

如果要定位更多元素,可以使用 for 循環:

for (i = 1; i <= $(this).children().length; i++) {
    let childImg =  $(this).children("img:nth-child("+ i +")");
    // Do stuff...
}
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                <li ><h6><strong>Extensive and flexible repair capabilities at any location</strong></h6></li>
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                <li ><h6><strong>Extensive and flexible repair capabilities at any location</strong></h6></li>
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