CSS line-height属性
行高 属性被用来设置一个文本行的高度。line-height属性的值可以是数字，长度或百分比。
示例
<html>
<head>
</head>
<body>
<p style = "width:300px; height:100px; border:2px solid green; padding:5px; margin:10px; line-height:30px;">
This paragraph is 300 pixels wide and 100 pixels high and here line height is 50 pixels.
</p>
</body>
</html>