使用ID通过ID或类选择嵌套元素
[英]Selecting a nested element by id or class with jquery
问题描述
I'm a bit confused how jquery searches through the DOM. 
我有点困惑jquery如何通过DOM搜索。 Does it select from the root node, similar to XPath / selector, or from the current no matter where they are, similar to XPath // selector? 它是从根节点（类似于XPath /选择器）还是从当前节点（无论它们在何处）（类似于XPath //选择器）进行选择？
I have the following setup: 我有以下设置：
<body>
<div id="contentSection">
//A bunch of nested DIVs follow
<div id="parentDIV">
<span>Selector1</span>
<select class="selector" id="first">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<span>Selector2</span>
<select class="selector" id="second">
<option value="A">A</option>
<option value="B">B</option>
<option value="C">C</option>
</select>
</div>
</div>
<div id="someOtherDIVs> </div>
<div id="someOtherDIVs> </div>
</body>
Now if I try to select the content section first, then filter by class or id, I can attach an event handler to the select element, but if I try to query the element directly, the event handler is never attached. 现在，如果我尝试先选择内容部分，然后按类或ID进行过滤，则可以将事件处理程序附加到select元素，但是如果我尝试直接查询该元素，则永远不会附加事件处理程序。
For example, this works: 例如，这有效：
$('#contentSection').change('.plotSelector', function(e)
But these do not: 但是这些不：
$('#first').change(function(e) ...
$('.selector').change(function(e) ...
Can someone explain why? 有人可以解释为什么吗？ Is there a way to select from the root any element anywhere in the DOM? 有没有办法从根中选择DOM中任何位置的任何元素？
Using jquery 2.1.1 使用jQuery 2.1.1
2 个解决方案
解决方案1
0 2016-11-29 17:18:49
Yes the selectors work across the DOM ( http://api.jquery.com/category/selectors/ ) 是的，选择器可跨DOM工作（ http://api.jquery.com/category/selectors/ ）
The fiddles supplied in the comments work, have you checked your console for errors, maybe the javascript isn't running completely. 注释中提供的小提琴有效，您是否检查过控制台是否有错误，可能是javascript不能完全运行。
解决方案2
0 2016-11-29 17:27:24
Is there a way to select from the root any element anywhere in the DOM?
So long as you start from document. 只要您从document.开始document. , the standard javascript methods all select from the root: ， 所有标准javascript方法都可以从根目录中进行选择：
-
document.getElementById(''); -
document.getElementsByClassName(''); -
document.getElementsByTagName(''); -
document.querySelector(''); -
document.querySelectorAll('');
声明:本站的技术帖子网页，遵循CC BY-SA 4.0协议，如果您需要转载，请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.