js登陆后隐藏button 急

这是登陆后隐藏button的控件我运行的时候总说页面有错误也不说什么错误大神们帮我看看
<script type="text/javascript">       function fdenglu()
{
      if  (Session("user_name")=Null)

              {
               //document.getElementById("Button1").style .visibility ='hidden';
                var denglu1=document.getElementById("Button1").style .visibility ='visible';              // document.getElementById("Button2").style .visibility ='hidden';
              // document.getElementById ("Button9").style .visibility ='visible';
              }
       else
         var denglu2=document.getElementById ("Button1").style .visibility ='hidden';

  }

  function fzhuce()
  {
  if (Session("user_name")=Null)
  var zhuce1=document.getElementById ("Button2").style .visibility ='visible';
  else
  var zhuce2=document.getElementById ("Button2").style .visibility ='hidden';
  }

  function fzhuxiao()
  {
  if (Session("user_name")=Null)
  var zhuxiao1=document.getElementById ("Button9").style .visibility ='hidden';
  var zhuxiao2=document.getElementById ("Button9").style .visibility ='visible';
  }

</script>
                    <input type="button" id ="Button1" value= "登陆" onclick ="fdenglu()"&"Button1_Click" />                      
                    <input type="button" id ="Button2" value= "注册" onclick ="fzhuce()"&"Button2_Click" />                       
                    <input type="button" id ="Button9" value= "注销" onclick ="fzhuxiao()"&"Button9_Click"/>

解决方案 »

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"Session" 是什么？
"="是赋值
"=="才能判断
session 是判断是否登陆
那全部代码如下:
<%@ Page Language="VB" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><script runat="server">    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs)

        Response.Redirect("Log-in.aspx")

    End Sub
    Protected Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs)
        Response.Redirect("Register1.aspx")
    End Sub
    Protected Sub Button3_Click(ByVal sender As Object, ByVal e As System.EventArgs)
        Response.Redirect("Happy.aspx")
    End Sub
    Protected Sub Button4_Click(ByVal sender As Object, ByVal e As System.EventArgs)
        Response.Redirect("Angry.aspx")
    End Sub
    Protected Sub Button5_Click(ByVal sender As Object, ByVal e As System.EventArgs)
        Response.Redirect("Sad.aspx")
    End Sub
    Protected Sub Button6_Click(ByVal sender As Object, ByVal e As System.EventArgs)
        Response.Redirect("Awkward.aspx")
    End Sub
    Protected Sub Button7_Click(ByVal sender As Object, ByVal e As System.EventArgs)
        Response.Redirect("Others.aspx")
    End Sub
    Protected Sub Button8_Click(ByVal sender As Object, ByVal e As System.EventArgs)
        Response.Redirect("HOT.aspx")
    End Sub
      Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
        '之前应有个登陆的判断否则会一直显示欢迎你和登陆按钮
        Dim user_name As String
        user_name = Session("user_name")
        Label1.Text = user_name & "欢迎你！"



    End Sub

</script>
<script type="text/javascript">
//  set conn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source= " & MapPath("database.mdb"));


        function fdenglu()
{
      if  (Session("user_name")=Null)

              {
                              var denglu1=document.getElementById("Button1").style .visibility ='visible';                         }
       else
         var denglu2=document.getElementById ("Button1").style .visibility ='hidden';

  }

  function fzhuce()
  {
  if (Session("user_name")=Null)
  var zhuce1=document.getElementById ("Button2").style .visibility ='visible';
  else
  var zhuce2=document.getElementById ("Button2").style .visibility ='hidden';
  }

  function fzhuxiao()
  {
  if (Session("user_name")=Null)
  var zhuxiao1=document.getElementById ("Button9").style .visibility ='hidden';
  var zhuxiao2=document.getElementById ("Button9").style .visibility ='visible';
  }

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>杂味</title>
    <style type="text/css">

    </style>
</head><body>
   <form id="Form1" runat="server">
    <div style="text-align: center; background-image: url(Images/Main/BackColor.jpg);">
        <table border="1" style="border-right: thin groove; border-top: thin groove; border-left: thin groove;
            border-bottom: thin groove" width="948" >
            <tr>
                <td style="width: 900px; position: static; height: 55px; border-right: #99cccc 0px solid; border-top: #99cccc 0px solid; border-left: #99cccc 0px solid; border-bottom: #99cccc 20px solid; text-align: right;" valign="middle">
                                           
                                           
                                           
                                           
                                          
                                           
                                           
                                           
                                         
                                           
                                           
                                          
                                           
                                           
                                           
                                           
                                           
                                  
                    <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
                         
                    <input type="button" id ="Button1" value= "登陆" onclick ="fdenglu()"&"Button1_Click" />                      
                    <input type="button" id ="Button2" value= "注册" onclick ="fzhuce()"&"Button2_Click" />                       
                    <input type="button" id ="Button9" value= "注销" onclick ="fzhuxiao()"&"Button9_Click"/>
            </td>
            </tr>
            <tr>
                <td style="width: 900px; height: 431px; position: static; background-image: url(Images/Main/BackColor1.jpg); border-right: #99cccc 0px solid; border-top: #99cccc 0px solid; border-left: #99cccc 0px solid; border-bottom: #99cccc 0px solid;" valign="middle">
                                   
                         
                            
                    <br />
                    <br />
                    <asp:Button ID="button3" runat="server" Text="喜" Font-Bold="True" Font-Size="XX-Large" Height="50px" Width="50px" BackColor="Transparent" OnClick="Button3_Click" />
                    <asp:Button ID="Button4" runat="server" Text="怒" Font-Bold="True" Font-Size="XX-Large" Height="50px" Width="50px" BackColor="Transparent" OnClick="Button4_Click"/>
                    <asp:Button ID="Button5" runat="server" Text="哀" Font-Bold="True" Font-Size="XX-Large" Height="50px" Width="50px" BackColor="Transparent" OnClick="Button5_Click"  />
                    <asp:Button ID="Button6" runat="server" Text="囧" Font-Bold="True" Font-Size="XX-Large" Height="50px" Width="50px" BackColor="Transparent" OnClick="Button6_Click"/><br />
                    <asp:Button ID="Button7" runat="server" Text="杂味" Font-Bold="True" Font-Size="Small" Height="39px" Width="46px" BackColor="Transparent" OnClick="Button7_Click"/>
                    <asp:Button ID="Button8" runat="server" Text="HOT!" Font-Bold="True" Font-Size="Small" Height="39px" Width="42px" BackColor="Transparent" OnClick="Button8_Click"/>
                    </td>
                    </tr>
            <tr>
                <td style="width: 900px; position: static; height: 51px; border-right: #99cccc 0px solid; border-top: #99cccc 0px solid; font-size: 10pt; border-left: #99cccc 0px solid; border-bottom: #99cccc 0px solid;" valign="middle">
                   </td>
            </tr>
        </table>
    </div>
</form>
</body>
</html>
回我吧急用啊
或者告诉我别的可能实现的方法
其实我做web的语言是vb
<script type="text/javascript">
var sessionName=<%=Session("user_name")%>function fdenglu()
{
  if (sessionName == null)
.......
    </script>
你js要访问session 要通过ajax的。
你可以页面加载的时候用个隐藏域保存登录状态。
if (sessionName == null||sessionName=="")
其实我后来发现只用
  If Session("user_name") Is Nothing Then

            Button1.Visible = True
            Button2.Visible = True
            Button9.Visible = False
        Else
            Button1.Visible = False
            Button2.Visible = False
            Button9.Visible = True就可以完成谢谢大家的回答啊