请记住， vertical-align:middle; 本身并没有用，您还需要设置line-height: line-height:400px; .

Remember that vertical-align: middle; is not to useful on its own, you also need to set the line-height: line-height:400px;.

如果您的< div> 中没有其他文本(可能只有一行)，这将很有用.

This is useful if you have no other text in your <div> (except maybe a single line).

工作示例: http://jsfiddle.net/kobi/ZfMYy/5/