js 提交表单的几种判断方法

<script language="javascript">
<!--
function xxg()
{
  if (frm.t11.value=="")
   {
 alert("简介");
 return false;
  }}
//-->
</script>
</head>

<form method="POST" action="" onsubmit="return xxg();" name=frm>
 <p><input type="text" name="t11" size="20">
 <input type="submit" value="提交">
 <input type="reset" value="重置" name="B2"></p>
</form>
--------
<script LANGUAGE="JavaScript">
function checkp()
{
  if (document.Formp.t11.value=="")
    {
     alert("请输入注册的企业全称！")
     document.Formp.t11.focus()
     document.Formp.t11.select()
     return
     }
   document.Formp.submit()
}
</SCRIPT>

<form method="POST" action="" name=Formp>
<input type="text" name="t11" size="20">
<input type="button" value="按钮" onclick="checkp()">
</form>
---js提交表单操作。
<% P_password="12344"%>
<%
password=request.form("password")

if Request("password")<>"" then   
      if password=P_password then
          session("logpassword")=password 
          session("fz_login") = "8"
   response.write "你是神"
   'response.end
     else
%>
 <script language=Javascript>
 alert("错误！麻烦你认真一点，请重新输入！");
 window.history.go(-1);
 </script>
<%
   end if
   else
%>
<form method="post" action="rar.asp" name="form">
<input type="text" name="password" size="20">
<input type="submit" value="提交">
</form>
<% end if%>