uTools-Manuals/docs/jQuery/callbacks.has.html

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<h1 class="entry-title">callbacks.has()</h1>
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所属分类:<span class="category"><a href="/category/callbacks-object/">回调对象</a></span>
<span class="pull-right">英文文档:<a href="https://api.jquery123.com/callbacks.has/" target="_blank">callbacks.has()</a></span>
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<span class="name">callbacks.has( callback )</span><span class="returns">返回: <a href="/Types/#Boolean">Boolean</a></span>
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<p class="desc"><strong>描述: </strong>确定列表中是否提供一个回调</p>
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<span class="version-details">添加的版本: <a href="/category/version/1.7/">1.7</a></span>callbacks.has( callback )</h4>
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<div><strong>callback</strong></div>
<div>类型: <a href="/Types/#Function">Function</a>()</div>
<div>用来查找的回调函数。</div>
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<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">使用 <code>callbacks.has()</code> 检查列表中是否提供一个回调:</span></h4>
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<pre><div class="container"><div class="line"><code><span class="comment">// a sample logging function to be added to a callbacks list</span></code></div></div><div class="container"><div class="line"><code><span class="keyword">var</span> foo = <span class="keyword">function</span>( value1, value2 ) {</code></div></div><div class="container"><div class="line"><code> console.log( <span class="string">"Received: "</span> + value1 + <span class="string">","</span> + value2 );</code></div></div><div class="container"><div class="line"><code>};</code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="comment">// a second function which will not be added to the list</span></code></div></div><div class="container"><div class="line"><code><span class="keyword">var</span> bar = <span class="keyword">function</span>( value1, value2 ) {</code></div></div><div class="container"><div class="line"><code> console.log( <span class="string">"foobar"</span> );</code></div></div><div class="container"><div class="line"><code>}</code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="keyword">var</span> callbacks = $.Callbacks();</code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="comment">// add the log method to the callbacks list</span></code></div></div><div class="container"><div class="line"><code>callbacks.add( foo );</code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="comment">// determine which callbacks are in the list</span></code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code>console.log( callbacks.has( foo ) );</code></div></div><div class="container"><div class="line"><code><span class="comment">// true</span></code></div></div><div class="container"><div class="line"><code>console.log( callbacks.has( bar ) );</code></div></div><div class="container"><div class="line"><code><span class="comment">// false</span></code></div></div></pre>
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