[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......
[0]
來引用它擴展 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 jQuery 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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<!-- <sc:text field="Event Description" runat="server" item="<%#Container.DataItem %>" /> -->
<ul >
<li ><h6><strong>lorem</strong></h6></li>
<li ><h6><strong>An assigned contact who knows you and your lorem analysis system</strong></h6></li>
<li ><h6><strong>Internet accessible on-demand information and an easy to use internet shop</strong></h6></li>
<li ><h6><strong>Extensive and flexible repair capabilities at any location</strong></h6></li>
<li ><h6><strong>Full Service Contracts</strong></h6></li>
<li ><h6><strong>Maintenance Contracts</strong></h6></li>
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<a><span id="imgDownArrow_0" class="glyphicon glyphicon-chevron-right " runat="server"> MoreInformation</span></a>
<div id="parent" class="dataContentSectionMessages" style="display:none">
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<!-- <sc:text field="Event Description" runat="server" item="<%#Container.DataItem %>" /> -->
<ul >
<li ><h6><strong>lorem</strong></h6></li>
<li ><h6><strong>An assigned contact who knows you and your lorem analysis system</strong></h6></li>
<li ><h6><strong>Internet accessible on-demand information and an easy to use internet shop</strong></h6></li>
<li ><h6><strong>Extensive and flexible repair capabilities at any location</strong></h6></li>
<li ><h6><strong>Full Service Contracts</strong></h6></li>
<li ><h6><strong>Maintenance Contracts</strong></h6></li>
</ul>
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</div>
</div>
<div>
<a><span id="imgDownArrow_0" class="glyphicon glyphicon-chevron-right " runat="server"> MoreInformation</span></a>
<div id="parent" class="dataContentSectionMessages" style="display:none">
<!-- repeater1 starts -->
<!-- <sc:text field="Event Description" runat="server" item="<%#Container.DataItem %>" /> -->
<ul >
<li ><h6><strong>lorem</strong></h6></li>
<li ><h6><strong>An assigned contact who knows you and your lorem analysis system</strong></h6></li>
<li ><h6><strong>Internet accessible on-demand information and an easy to use internet shop</strong></h6></li>
<li ><h6><strong>Extensive and flexible repair capabilities at any location</strong></h6></li>
<li ><h6><strong>Full Service Contracts</strong></h6></li>
<li ><h6><strong>Maintenance Contracts</strong></h6></li>
</ul>
<!-- repeater1 ends -->
</div>
</div>
</asp:Repeater>
</body>
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<script src="jquery.js"></script>
<script src="bootstrap.js"></script>
<script>
$(function () {
$('a').click(function() {
$(this).parent().children('.dataContentSectionMessages').slideToggle();
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