呵呵給妳吧
<form name="loginmail" onsubmit="return chkinput2(this);" action=".com">@21cn.com</option>
<option value="163.net">@163.net</option>
<option value="tom.com">@tom.com</option>
<option value="163.com">@163.com</option>
<option value="vip.163.com">@vip.163.com</option>
<option value="sohu.com">@sohu.com</option>
<option value="263.net">@263.net</option>
<option value="sina.com">@sina.com</option>
<option value="vip.sina.com">@vip.sina.com</option>
<option value="mail.china.com">@mail.china.com</option>
<option value="china.com">@china.com</option>
<option value="263.net">@netease.com</option>
<option value="yeah.net">@yeah.net</option>
<option value="etang.com">@etang.com</option>
<option value="fm365.com">@fm365.com</option>
<option value="yahoo.com.cn">@yahoo.com.cn</option>
<option value="xinhuanet.com">@xinhuanet.com</option>
<option value="126.com">@126.com</option>
<option value="qs163.com">@qs163.com</option>
</select> <BR>
<input type="submit" name="s1" class="button1" value=" 登陸郵箱 ">
</td>
</tr>
</table>
</form>