jQuery gets the previous, next, parent element, and child element of an element
1. Problem description
1. First is this HTML structure:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Title</title>
<script src="https://cdn.staticfile.org/jquery/1.10.2/jquery.min.js"></script>
</head>
<body>
<div id="parent">
<div id="firstSon">
<span id="notSelect">其他</span>
</div>
<div id="secondSon">
<div id="nowSelect">
<span id="grandSon">当前</span>
</div>
</div>
<div id="firstSon">
<span id="notSelect">其他</span>
</div>
</div>
</body>
</html>
2. First, the jQuery selector points to the div element with id="nowSelect"
JS code using jQuery statement:
<script>
var selectObj = $("#nowSelect");
console.log(selectObj[0]);
</script>
operation result:
<div id="nowSelect">
<span id="grandSon">当前</span>
</div>
2. Get other elements
1. Get its parent element (.parent())
Code:
<script>
var selectObj = $("#nowSelect").parent();
console.log(selectObj[0]);
</script>
operation result:
<div id="secondSon">
<div id="nowSelect">
<span id="grandSon">当前</span>
</div>
</div>
注：
（1）jQuery.parents(expr)类似于jQuery.parents(expr),但是是查找所有祖先元素，不限于父元素；
（2）jQuery.parent()可以传入expr进行过滤（jQuery.parent(expr)），比如$("span").parent()或者$("span").parent(".class").
2. Get its child elements (.children())
Code:
<script>
var selectObj = $("#nowSelect").children();
console.log(selectObj[0]);
</script>
operation result:
<span id="grandSon">当前</span>
3. Get its previous element (.prev())
Code:
<script>
var selectObj = $("#nowSelect").parent().prev();
console.log(selectObj[0]);
</script>
operation result:
<div id="firstSon">
<span id="notSelect">其他</span>
</div>
注：jQuery.prevAll()返回所有之前的兄弟节点
4. Get its next element (.next())
Code:
<script>
var selectObj = $("#nowSelect").parent().next();
console.log(selectObj[0]);
</script>
operation result:
<div id="thirdSon">
<span id="notSelect">其他</span>
</div>
注：jQuery.nextAll()返回所有之后的兄弟节点
5. Get the nearest element whose attribute is XXX (.closest())
Code:
<script>
var selectObj = $("#grandSon").closest("div");
console.log(selectObj[0]);
</script>
operation result:
<div id="nowSelect">
<span id="grandSon">当前</span>
</div>
3. Others
1. Find the first child element of the same parent (.first())
Code:
<script>
var selectObj = $("#parent div").first();
console.log(selectObj[0]);
</script>
operation result:
<div id="firstSon">
<span id="notSelect">其他</span>
</div>
2. Find the last child element of the same parent (.last())
Code:
<script>
var selectObj = $("#parent div").last();
console.log(selectObj[0]);
</script>
operation result:
<div id="thirdSon">
<span id="notSelect">其他</span>
</div>