javascript 检查元素是否包含特定的子元素
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Check if an element contains a specific child element
提问by lomse
I have many divs which sometimes contain links. I want check whether or not they have a link. This is my attempt:
我有很多divs 有时包含链接。我想检查他们是否有链接。这是我的尝试：
var container = $(this).closest('.content').find('.text');
//Check if text contains a tags
if(container+':has(a)'){
alert('contain link');
}
else{
alert('no link found'); //Alert "contain link" even if no link is found.
}
By doing container.html()I can see the exact content of containerincluding anchor tags, but my code above will always say that it cannot find the anchor tag.
通过这样做，container.html()我可以看到container包含锚标记的确切内容，但是我上面的代码总是说它找不到锚标记。
Could someone tell me what I am doing wrong?
有人能告诉我我做错了什么吗？
采纳答案by Dallas
Change to this:
改成这样：
if(container.find("a").length){ ...
containeris a jquery object and .find()is a function of that object that finds elements within it. A length greater than 0 will mean it finds an anchor tag and it will evaluate to true.
container是一个 jquery 对象，并且.find()是该对象的一个函数，用于在其中查找元素。大于 0 的长度将意味着它找到了一个锚标签，并将评估为真。
Edit:
编辑：
Also, to explain why your example isn't working. When you do container+':has(a)', you are doing a string concatenation which runs toString()on your object (converting it to "[object Object]"). So you end up with the string "[object Object]:has(a)" which will always evaluate to true.
另外，解释为什么你的例子不起作用。当您这样做时container+':has(a)'，您正在执行toString()在您的对象上运行的字符串连接（将其转换为“[object Object]”）。所以你最终得到字符串“[object Object]:has(a)”，它总是评估为真。
回答by Rory McCrossan
You can use the lengthproperty of a selector to determine if any elements were found. Try this:
您可以使用length选择器的属性来确定是否找到了任何元素。试试这个：
var $container = $(this).closest('.content').find('.text');
if ($('a', $container).length) {
alert('Contains links');
}
else {
alert('No links found');
}
回答by Vitaly Muminov
Change
改变
if(container+':has(a)'){
To
到
if(container.has('a').size()){
container is an jquery object, not a selector string
容器是一个 jquery 对象，而不是一个选择器字符串
