<%
  if  select1="teacher" then  
  %>
<form action="add.asp" id="FORM1" method="get" name="FORM1"onSubmit="javascript: return validate(this);" >
    <table width="100%" >
            <tr>
                <td >
              <input type="submit" name="Submit" value="提交">
                   <input type="reset" name="reset" value="重设">
                </td>
           </tr>

         </table>
      </form>
      <%else%>
      <form action="add1.asp" id="FORM1" method="get" name="FORM1" onSubmit="javascript: return validate1(this);">
            <table align=center width="100%">
             <tr>
                <td >
              <input type="submit" name="Submit" value="提交">
                   <input type="reset" name="reset" value="重设">
                </td>
            </tr>        
            </table>
      </form>
<%end if%>
表的内容略了，为什么每次提交都是到add.asp这个页面呢？谢谢！

if  select1="teacher" then  
根据你的问题描述证明这个判断有问题，判断的select1总是等于teacher

<%
if action="add" then
if name<>"" then
%>
<form id="form1" name="form1" method="post" action="">
  <table width="100%" border="0">
    <tr>
      <td colspan="2"><div align="center">注册</div></td>
    </tr>
    <tr>
      <td><div align="right">用户名:</div></td>
      <td><label>
        <input type="text" name="textfield" />
      </label></td>
    </tr>
    <tr>
      <td><div align="right">密码:</div></td>
      <td><label>
        <input type="text" name="textfield2" />
      </label></td>
    </tr>
    <tr>
      <td colspan="2"><label>
        <div align="center">
          <input type="submit" name="Submit" value="提交" />
          <input type="reset" name="Submit2" value="重置" />
          </div>
      </label></td>
    </tr>
  </table>
</form>
<%else%>
<form id="form1" name="form1" method="post" action="">
  <table width="100%" border="0">
    <tr>
      <td colspan="2"><div align="center">注册</div></td>
    </tr>
    <tr>
      <td><div align="right">用户名:</div></td>
      <td><label>
        <input type="text" name="textfield" />
      </label></td>
    </tr>
    <tr>
      <td><div align="right">密码:</div></td>
      <td><label>
        <input type="text" name="textfield2" />
      </label></td>
    </tr>
    <tr>
      <td colspan="2"><label>
        <div align="center">
          <input type="submit" name="Submit" value="提交" />
          <input type="reset" name="Submit2" value="重置" />
          </div>
      </label></td>
    </tr>
  </table>
</form>
<%
 end if
end if
%>

因为select1是从上一页面得到，可以是学生，也可以是老师，if是老师then

else 就是学生了

有没有form嵌套？

两个form就要使用两个name

<form name="form1" action="add.asp" method="get">

</form>

<form name="form2" action="add1.asp" method="get">

</form>