代码示例：（标识：css_overflow_intro）
<!DOCTYPE html>
<html>
<head>
<style>
#overflowTest {
background: #4CAF50;
color: white;
padding: 15px;
width: 50%;
height: 100px;
overflow: scroll;
border: 1px solid #ccc;
}
</style>
</head>
<body>
<h1>CSS 溢出</h1>
<p>overflow 属性控制着当内容太大以至于区域无法容纳时发生的情况。</p>
<div id="overflowTest">This text is really long and the height of its container is only 100 pixels. Therefore, a scrollbar is added to help the reader to scroll the content. Shanghai is one of the four direct-administered municipalities of the People's Republic of China. Welcome to Shanghai! The city is located on the southern estuary of the Yangtze, with the Huangpu River flowing through it. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Nam liber tempor cum soluta nobis eleifend option congue nihil imperdiet doming id quod mazim placerat facer possim assum. Typi non habent claritatem insitam; est usus legentis in iis qui facit eorum claritatem.</div>
</body>
</html>
