jQuery 如何计算孩子的数量？
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How can I count the number of children?
提问by aneuryzm
I have a list
我有一个清单
<ul>
<li>
<li>
<li>
...
</ul>
I need jQuery to count the number of items in my list.
我需要 jQuery 来计算列表中的项目数。
回答by Nick Craver
You can use .length, like this:
你可以使用.length，像这样：
var count = $("ul li").length;
.lengthtells how many matches the selector found, so this counts how many <li>under <ul>elements you have...if there are sub-children, use "ul > li"instead to get only directchildren. If you have other <ul>elements in your page, just change the selector to match only his one, for example if it has an ID you'd use "#myListID > li".
.length告诉选择器找到多少匹配项，因此这会计算您拥有的<li>下<ul>元素的数量……如果有子子项，请改用"ul > li"仅获取直接子项。如果您<ul>的页面中有其他元素，只需更改选择器以仅匹配他的元素，例如，如果它具有您要使用的 ID "#myListID > li"。
In other situations where you don't know the child type, you can use the *(wildcard) selector, or .children(), like this:
在您不知道子类型的其他情况下，您可以使用*（通配符）选择器或.children()，如下所示：
var count = $(".parentSelector > *").length;
or:
或者：
var count = $(".parentSelector").children().length;
回答by Zach Saucier
You don't need jQuery for this. You can use JavaScript's .childNodes.length.
为此，您不需要 jQuery。您可以使用 JavaScript 的.childNodes.length.
Just make sure to subtract 1 if you don't want to include the default text node (which is empty by default). Thus, you'd use the following:
如果您不想包含默认文本节点（默认为空），请确保减去 1。因此，您将使用以下内容：
var count = elem.childNodes.length - 1;
回答by Zach Saucier
Try to get using:
尝试使用：
var count = $("ul > li").size();
alert(count);
回答by Oguzhan
What if you are using this to determine the current selector to find its children
so this holds: <ol>then there is <li>s under how to write a selector
var count = $(this+"> li").length;wont work..
如果您使用它来确定当前选择器以找到它的子代怎么办，所以这成立：<ol>那么<li>如何编写选择器将
var count = $(this+"> li").length;不起作用..
回答by Youssof H.
You can do this using jQuery:
您可以使用 jQuery 执行此操作：
This method gets a list of its children then counts the length of that list, as simple as that.
此方法获取其子项的列表，然后计算该列表的长度，就这么简单。
$("ul").find("*").length;
The find() method traverses DOM downwards along descendants, all the way down to the last descendant.
find() 方法沿着后代向下遍历 DOM，一直向下遍历到最后一个后代。
Note:children() method traverses a single level down the DOM tree.
注意：children() 方法向下遍历 DOM 树的单个级别。
