1:

<a href="userAction.do?flag=user_regist"> registered </a>

2:

<a href="<s:url action="userAction">
<s:param name="flag" value="'user_regist'" />
</s:url>"> registered </a>
// Notice here action Names are in the sturts.xml The name of the configuration in.
[\s\S ]*\n

3:

javascript the location.href . A little.