2019-04-21 11:50:48 +08:00

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<article class="" id="post-">
<header class="entry-header">
<h1 class="entry-title">.has()</h1>
<div class="entry-meta">
所属分类:<span class="category"><a href="/category/traversing/">遍历</a> &gt; <a href="/category/traversing/filtering/">过滤</a></span>
<span class="pull-right">英文文档:<a href="https://api.jquery123.com/has/" target="_blank">.has()</a></span>
</div><!-- .entry-meta -->
</header><!-- .entry-header -->
<!-- .entry-header -->
<div class="entry-content">
<article class="entry method" id="has1"><h2 class="section-title">
<span class="name">.has( selector )</span><span class="returns">返回: <a href="/Types/#jQuery">jQuery</a></span>
</h2>
<div class="entry-wrapper">
<p class="desc"><strong>描述: </strong>
筛选匹配元素集合中的那些有相匹配的选择器或DOM元素的后代元素。</p>
<ul class="signatures">
<li class="signature" id="has-selector">
<h4 class="name">
<span class="version-details">添加的版本: <a href="/category/version/1.4/">1.4</a></span>.has( selector )</h4>
<ul><li>
<div><strong>selector</strong></div>
<div>类型: <a href="/Types/#String">String</a>
</div>
<div>一个用于匹配元素的选择器字符串。</div>
</li></ul>
</li>
<li class="signature" id="has-contained">
<h4 class="name">
<span class="version-details">添加的版本: <a href="/category/version/1.4/">1.4</a></span>.has( contained )</h4>
<ul><li>
<div><strong>contained</strong></div>
<div>类型: <a href="/Types/#Element">Element</a>
</div>
<div>用于匹配元素的DOM元素。</div>
</li></ul>
</li>
</ul>
<div class="longdesc" id="entry-longdesc">
<p>如果提供一个jQuery对象代表DOM元素集合 <code>.has()</code> 方法会用其子集创建一个新的jQuery对象。提供的选择器会一一测试原先那些匹配元素的后代含有匹配后代的元素会保留在结果中。</p>
<p>下面是一个嵌套列表的页面:</p>
<div class="syntaxhighlighter xml nogutter">
<table>
<tbody>
<tr>
<td class="gutter">
<div class="line n1">1</div>
<div class="line n2">2</div>
<div class="line n3">3</div>
<div class="line n4">4</div>
<div class="line n5">5</div>
<div class="line n6">6</div>
<div class="line n7">7</div>
<div class="line n8">8</div>
<div class="line n9">9</div>
<div class="line n10">10</div>
<div class="line n11">11</div>
</td>
<td class="code">
<pre><div class="container"><div class="line"><code> <span class="tag">&lt;<span class="title">ul</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> <span class="tag">&lt;<span class="title">li</span>&gt;</span>list item 1<span class="tag">&lt;/<span class="title">li</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> <span class="tag">&lt;<span class="title">li</span>&gt;</span>list item 2</code></div></div><div class="container"><div class="line"><code> <span class="tag">&lt;<span class="title">ul</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> <span class="tag">&lt;<span class="title">li</span>&gt;</span>list item 2-a<span class="tag">&lt;/<span class="title">li</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> <span class="tag">&lt;<span class="title">li</span>&gt;</span>list item 2-b<span class="tag">&lt;/<span class="title">li</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> <span class="tag">&lt;/<span class="title">ul</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> <span class="tag">&lt;/<span class="title">li</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> <span class="tag">&lt;<span class="title">li</span>&gt;</span>list item 3<span class="tag">&lt;/<span class="title">li</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> <span class="tag">&lt;<span class="title">li</span>&gt;</span>list item 4<span class="tag">&lt;/<span class="title">li</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">ul</span>&gt;</span></code></div></div></pre>
</td>
</tr>
</tbody>
</table>
</div>
<p>我们可以用如下方式对列表项集合应用这个方法:</p>
<div class="syntaxhighlighter javascript nogutter">
<table>
<tbody>
<tr>
<td class="gutter">
<div class="line n1">1</div>
</td>
<td class="code">
<pre><div class="container"><div class="line"><code>$(<span class="string">'li'</span>).has(<span class="string">'ul'</span>).css(<span class="string">'background-color'</span>, <span class="string">'red'</span>);</code></div></div></pre>
</td>
</tr>
</tbody>
</table>
</div>
<p>
结果是 item 2 背景变成了红色,因为只有这个 <code>&lt;li&gt;</code> 含有 <code>&lt;ul&gt;</code> 后代。</p>
</div>
<section class="entry-examples" id="entry-examples"><header><h2 class="underline">例子:</h2></header><div class="entry-example" id="example-0">
<h4><span class="desc">检测是否一个元素在另一个之内。</span></h4>
<div class="syntaxhighlighter xml ">
<table>
<tbody>
<tr>
<td class="gutter">
<div class="line n1">1</div>
<div class="line n2">2</div>
<div class="line n3">3</div>
<div class="line n4">4</div>
<div class="line n5">5</div>
<div class="line n6">6</div>
<div class="line n7">7</div>
<div class="line n8">8</div>
<div class="line n9">9</div>
<div class="line n10">10</div>
<div class="line n11">11</div>
<div class="line n12">12</div>
<div class="line n13">13</div>
<div class="line n14">14</div>
<div class="line n15">15</div>
<div class="line n16">16</div>
<div class="line n17">17</div>
<div class="line n18">18</div>
<div class="line n19">19</div>
</td>
<td class="code">
<pre><div class="container"><div class="line"><code><span class="doctype">&lt;!DOCTYPE html&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">html</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">head</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> <span class="tag">&lt;<span class="title">style</span>&gt;</span><span class="css"></span></code></div></div><div class="container"><div class="line"><code> <span class="class">.full</span> <span class="rules">{ <span class="rule"><span class="attribute">border</span>:<span class="value"> <span class="number">1</span>px solid red;</span></span> <span class="rule">}</span></span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">style</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> <span class="tag">&lt;<span class="title">script</span> <span class="attribute">src</span>=<span class="value">"https://code.jquery.com/jquery-latest.js"</span>&gt;</span><span class="javascript"></span><span class="tag">&lt;/<span class="title">script</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">head</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">body</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">ul</span>&gt;</span><span class="tag">&lt;<span class="title">li</span>&gt;</span>Does the UL contain an LI?<span class="tag">&lt;/<span class="title">li</span>&gt;</span><span class="tag">&lt;/<span class="title">ul</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">script</span>&gt;</span><span class="javascript"></span></code></div></div><div class="container"><div class="line"><code> $(<span class="string">"ul"</span>).append(<span class="string">"&lt;li&gt;"</span> + ($(<span class="string">"ul"</span>).has(<span class="string">"li"</span>).length ? <span class="string">"Yes"</span> : <span class="string">"No"</span>) + <span class="string">"&lt;/li&gt;"</span>);</code></div></div><div class="container"><div class="line"><code> $(<span class="string">"ul"</span>).has(<span class="string">"li"</span>).addClass(<span class="string">"full"</span>);</code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">script</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">body</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">html</span>&gt;</span></code></div></div></pre>
</td>
</tr>
</tbody>
</table>
</div>
<h4>Demo:</h4>
<div class="demo code-demo"></div>
</div></section>
</div></article> </div>
</article>