如何用jQuery来计算子元素
使用jQuery来计算HTML文件中子元素的数量是非常简单的。比如说。如果你有一个由许多子元素组成的父元素,那么你可以使用.length或.children().length方法,如下所述。
语法:
var len=$("#parentID").length;
或
var count = $("#parentId").children().length;
示例 1:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<title>Count child elements using Jquery</title>
<meta name="viewport"
content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="">
</head>
<body>
<div id="parentID">
<p>Red</p>
<p>White</p>
<p>Green</p>
<p>Black</p>
<p>Blue</p>
<p>Orange</p>
</div>
<script src="https://code.jquery.com/jquery-3.5.0.min.js"
integrity="sha256-xNzN2a4ltkB44Mc/Jz3pT4iU1cmeR0FkXs4pru/JxaQ="
crossorigin="anonymous">
</script>
<script>
// Here we count the child element in parentID
var count = $("#parentID p").length;
document.writeln(count);
</script>
</body>
</html>
输出:
示例 2:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
<title>Count child elements using jQuery.</title>
<script src=
"https://code.jquery.com/jquery-3.4.1.js">
</script>
</head>
<body>
<div id="parentId">
<ul>
<li>1 child</li>
<li>2 child</li>
<li>3 child</li>
<li>4 child</li>
<li>5 child</li>
</ul>
</div>
<script>
var count = $("#parentId ul").children().length;
document.writeln(count);
</script>
</body>
</html>
输出: