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<title>Bubble in JavaScript DOM</title>
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<h1>Bubble in JavaScript DOM</h1>
<p>DOM樹的結構是：</p>
<pre><code>
UL
- LI
- A
- SPAN
</code></pre>
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<li><a href="#"><span>阿秀</span></a></li>
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<p>滑鼠進入UL的任何一個子元素，如果不停止冒泡，我們從UL到SPAN都定義了滑鼠懸停（<code>mouseover</code>）事件，這個事件會上升了UL，進而從滑鼠所進入的元素到UL元素都會有紅色的邊。</p>
<li><a href="#"><span>俊秀</span></a></li>
<p>如果停止冒泡，事件不會上升，我們就可以擷取精确的滑鼠進入元素。</p>
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