怎样让文字自动换行?

Question

<div>
....
<div>

Answer 1

本来就是自动换行，除非长字符串，如aaaaaaaaaaa
解决方法：style="word-break:break-all"标点符号，如,,,,,,,,,,,
解决方法：style="word-wrap:break-word"

Answer 2

<table border="1" width="100" height="200">
  <td style="word-wrap: break-all;">
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
</td>
 </tr>
</table>or 
<table border="1" width="100" height="200">
  <td style="word-wrap: break-word;">
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
</td>
 </tr>
</table>
为何都没有效果?
给你例子吧.