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Detailed explanation of hierarchical selector usage examples in JQuery_jquery

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WBOYOriginal
2016-05-16 15:58:201353browse

The examples in this article describe the usage of hierarchical selectors in JQuery. Share it with everyone for your reference. The details are as follows:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>层次选择器</title>
<script src="jquery-1.6.2.min.js" type="text/javascript"></script>
<script type="text/javascript">
$(function () {
 //------1.在给定的祖先元素下匹配所有后代元素
 //(包含了子元素,以及子元素的元素,一直往下延伸)
 var $divs = $("#main div");
 for (var i = 0; i < $divs.length; i++) {
 alert($divs.get(i).id);
 }
 //------2.在给定的父元素下匹配所有子元素,只包括直接子元素
 //(不包含子元素的子元素)
 var $divs = $("#main > div");
 for (var i = 0; i < $divs.length; i++) {
 alert($divs.get(i).id);
 }
 //-----3.prev + next $("lable + input ") : 匹配所有紧接在prev后的next元素
 //注意:只能去到第一个,并且是紧挨着的,如果不是紧挨着div1后面的则取不到
 //.....<1>.例子1
 var $divBrother = $("#div1 + div"); //用#div1 ID选择器 ,只取到div2
 alert($divBrother.get(0).id);
 //.....<2>.例子2
 var $divBrothers = $("div + div"); 
 //用div 标签选择器,相邻的div都能取到 divSun1(和divSun相邻),div2(和div1相邻)
 for (var i = 0; i < $divBrothers.length; i++) {
 alert($divBrothers.get(i).id);
 }
 //-----4.prev ~ siblins
 //$("form ~ input") : 匹配prev元素之后的所有siblings元素 
 //注意:在匹配之后的元素,不包含该元素在内,
 //并且siblings匹配的是和prev同辈的元素,其后辈元素不被匹配。
 var $divBrothers = $("#main ~ div");
 for (var i = 0; i < $divBrothers.length; i++) { //得到main1,main2,main3
 alert($divBrothers.get(i).id);
 }
 }
);
</script>
</head>
<body>
<div id="main">
 <div id="div1" class="myDiv">我是div1
 <div id="divSun">我是孙子div
  <div id="divSunSun">我是孙子的孙子div</div>
 </div>
 <div id="divSun1">我是孙子div</div>
 </div>
 <div id="div2" class="myDiv">我是div2</div>
</div>
<div id="main1"></div>
<div id="main2"></div>
<input type="button" value="button" />
<div id="main3"></div>
</body>
</html>

Readers who are interested in more content related to jquery selector can check out the special topic of this site: "Summary of jquery selector usage"

I hope this article will be helpful to everyone’s jQuery programming.

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