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---
title: MouseEvent.relatedTarget
slug: Web/API/MouseEvent/relatedTarget
translation_of: Web/API/MouseEvent/relatedTarget
---
<div>{{APIRef("DOM Events")}}</div>
<div>只读属性<strong><code>MouseEvent.relatedTarget</code></strong> 是鼠标事件的次要目标（如果存在），它包括：</div>
<table class="standard-table" style="width: auto;">
<tbody>
<tr>
<td class="header">事件名称</td>
<td class="header"><code>target</code></td>
<td class="header"><code>relatedTarget</code></td>
</tr>
<tr>
<td>{{Event("focusin")}}</td>
<td>{{domxref("EventTarget")}} 获取焦点</td>
<td>{{domxref("EventTarget")}} 失去焦点</td>
</tr>
<tr>
<td>{{Event("focusout")}}</td>
<td>{{domxref("EventTarget")}} 失去焦点</td>
<td>The {{domxref("EventTarget")}} 获取焦点</td>
</tr>
<tr>
<td>{{Event("mouseenter")}}</td>
<td>指针设备进入{{domxref("EventTarget")}}</td>
<td>指针设备离开{{domxref("EventTarget")}}</td>
</tr>
<tr>
<td>{{Event("mouseleave")}}</td>
<td>指针设备离开 {{domxref("EventTarget")}}</td>
<td>指针设备进入 {{domxref("EventTarget")}}</td>
</tr>
<tr>
<td>{{Event("mouseout")}}</td>
<td>指针设备离开 {{domxref("EventTarget")}}</td>
<td>The {{domxref("EventTarget")}}</td>
</tr>
<tr>
<td>{{Event("mouseover")}}</td>
<td>指针设备进入 {{domxref("EventTarget")}}</td>
<td>指针设备离开 {{domxref("EventTarget")}}</td>
</tr>
<tr>
<td>{{Event("dragenter")}}</td>
<td>指针设备进入 {{domxref("EventTarget")}}</td>
<td>指针设备离开 {{domxref("EventTarget")}}</td>
</tr>
<tr>
<td>{{Event("dragexit")}}</td>
<td>指针设备离开 {{domxref("EventTarget")}}</td>
<td>指针设备进入 {{domxref("EventTarget")}}</td>
</tr>
</tbody>
</table>
<p>如果事件没有次要目标，<code>relatedTarget</code> 将返回 <code>null</code>.</p>
<h2 id="语法">语法</h2>
<pre class="syntaxbox">var <em>target</em> = <em>instanceOfMouseEvent</em>.relatedTarget
</pre>
<h3 id="返回值">返回值</h3>
<p> {{domxref("EventTarget")}} 对象或者 <code>null</code>.</p>
<h2 id="示例">示例</h2>
<p>尝试将你的鼠标移入移出红色和蓝色方块。</p>
<h3 id="HTML">HTML</h3>
<pre class="brush: html"><body id="body">
<div id="outer">
<div id="red"></div>
<div id="blue"></div>
</div>
<p id="log"></p>
</body></pre>
<h3 id="CSS">CSS</h3>
<pre class="brush: css">#outer {
width: 250px;
height: 125px;
display: flex;
}
#red {
flex-grow: 1;
background: red;
}
#blue {
flex-grow: 1;
background: blue;
}
#log {
max-height: 120px;
overflow-y: scroll;
}</pre>
<h3 id="JavaScript">JavaScript</h3>
<pre class="brush: js">const mouseoutLog = document.getElementById('log'),
red = document.getElementById('red'),
blue = document.getElementById('blue');
red.addEventListener('mouseover', overListener);
red.addEventListener('mouseout', outListener);
blue.addEventListener('mouseover', overListener);
blue.addEventListener('mouseout', outListener);
function outListener(event) {
let related = event.relatedTarget ? event.relatedTarget.id : "unknown";
mouseoutLog.innerText = `\nfrom ${event.target.id} into ${related} ${mouseoutLog.innerText}`;
}
function overListener(event) {
let related = event.relatedTarget ? event.relatedTarget.id : "unknown";
log.innerText = `\ninto ${event.target.id} from ${related} ${mouseoutLog.innerText}`;
}
</pre>
<h3 id="Result">Result</h3>
<p>{{EmbedLiveSample("Example", 700, 280)}}</p>
<h2 id="详述">详述</h2>
<table class="standard-table">
<tbody>
<tr>
<th scope="col">Specification</th>
<th scope="col">Status</th>
<th scope="col">Comment</th>
</tr>
<tr>
<td>{{SpecName('DOM3 Events','#widl-MouseEvent-relatedTarget','MouseEvent.relatedTarget')}}</td>
<td>{{Spec2('DOM3 Events')}}</td>
<td>No change from {{SpecName('DOM2 Events')}}.</td>
</tr>
<tr>
<td>{{SpecName('DOM2 Events','#Events-MouseEvent','MouseEvent.altkey')}}</td>
<td>{{Spec2('DOM2 Events')}}</td>
<td>Initial definition.</td>
</tr>
</tbody>
</table>
<h2 id="浏览器兼容性">浏览器兼容性</h2>
<p>{{Compat("api.MouseEvent.relatedTarget")}}</p>
<h2 id="另见">另见</h2>
<ul>
<li>{{ domxref("MouseEvent") }}</li>
<li><a href="/en-US/docs/DOM/event/Comparison_of_Event_Targets" title="DOM/event/Comparison_of_Event_Targets">Comparison of Event Targets</a></li>
</ul>
|
