下面的代码注意是针对搜索引擎做出一些适当的内容显示，但这样对于seo不好。不建议使用。作为学习参考。

代码如下:
<%
function GetBot()
''查询蜘蛛
dim s_agent
GetBot=""
s_agent=Request.ServerVariables("HTTP_USER_AGENT") ‘关键判断语句
if instr(1,s_agent,"googlebot",1) >0 then
GetBot="google"
end if
if instr(1,s_agent,"msnbot",1) >0 then
GetBot="MSN"
end if
if instr(1,s_agent,"slurp",1) >0 then
GetBot="Yahoo"
end if
if instr(1,s_agent,"baiduspider",1) >0 then
GetBot="baidu"
end if
if instr(1,s_agent,"sohu-search",1) >0 then
GetBot="Sohu"
end if
if instr(1,s_agent,"lycos",1) >0 then
GetBot="Lycos"
end if
if instr(1,s_agent,"robozilla",1) >0 then
GetBot="Robozilla"
end if
end function
if GetBot="baidu" then
''给百度定制的内容
elseif GetBot="google" then
''给google 定制的内容
end if
%>

下面是比较完整的代码需要的朋友也可以参考下。里面还包括了一些客户端信息。
代码如下:
Class SystemInfo_Cls
Public Browser, version, platform, IsSearch, AlexaToolbar
Private Sub Class_Initialize()
Dim Agent, Tmpstr
IsSearch = False
If Not IsEmpty(Session("SystemInfo_Cls")) Then
Tmpstr = Split(Session("SystemInfo_Cls"), "|||")
Browser = Tmpstr(0)
version = Tmpstr(1)
platform = Tmpstr(2)
AlexaToolbar = Tmpstr(4)
If Tmpstr(3) = "1" Then
IsSearch = True
End If
Exit Sub
End If
Browser = "unknown"
version = "unknown"
platform = "unknown"
Agent = Request.ServerVariables("HTTP_USER_AGENT")
If InStr(Agent, "Alexa Toolbar") > 0 Then
AlexaToolbar = "YES"
Else
AlexaToolbar = "NO"
End If
If Left(Agent, 7) = "Mozilla" Then ''有此标识为浏览器
Agent = Split(Agent, ";")
If InStr(Agent(1), "MSIE") > 0 Then
Browser = "Internet Explorer "
version = Trim(Left(Replace(Agent(1), "MSIE", ""), 6))
ElseIf InStr(Agent(4), "Netscape") > 0 Then
Browser = "Netscape "
Tmpstr = Split(Agent(4), "/")
version = Tmpstr(UBound(Tmpstr))
ElseIf InStr(Agent(4), "rv:") > 0 Then
Browser = "Mozilla "
Tmpstr = Split(Agent(4), ":")
version = Tmpstr(UBound(Tmpstr))
If InStr(version, ")") > 0 Then
Tmpstr = Split(version, ")")
version = Tmpstr(0)
End If
End If
If InStr(Agent(2), "NT 5.2") > 0 Then
platform = "Windows 2003"
ElseIf InStr(Agent(2), "Windows CE") > 0 Then
platform = "Windows CE"
ElseIf InStr(Agent(2), "NT 5.1") > 0 Then
platform = "Windows XP"
ElseIf InStr(Agent(2), "NT 4.0") > 0 Then
platform = "Windows NT"
ElseIf InStr(Agent(2), "NT 5.0") > 0 Then
platform = "Windows 2000"
ElseIf InStr(Agent(2), "NT") > 0 Then
platform = "Windows NT"
ElseIf InStr(Agent(2), "9x") > 0 Then
platform = "Windows ME"
ElseIf InStr(Agent(2), "98") > 0 Then
platform = "Windows 98"
ElseIf InStr(Agent(2), "95") > 0 Then
platform = "Windows 95"
ElseIf InStr(Agent(2), "Win32") > 0 Then
platform = "Win32"
ElseIf InStr(Agent(2), "Linux") > 0 Then
platform = "Linux"
ElseIf InStr(Agent(2), "SunOS") > 0 Then
platform = "SunOS"
ElseIf InStr(Agent(2), "Mac") > 0 Then
platform = "Mac"
ElseIf UBound(Agent) > 2 Then
If InStr(Agent(3), "NT 5.1") > 0 Then
platform = "Windows XP"
End If
If InStr(Agent(3), "Linux") > 0 Then
platform = "Linux"
End If
End If
If InStr(Agent(2), "Windows") > 0 And platform = "unknown" Then
platform = "Windows"
End If
ElseIf Left(Agent, 5) = "Opera" Then ''有此标识为浏览器
Agent = Split(Agent, "/")
Browser = "Mozilla "
Tmpstr = Split(Agent(1), " ")
version = Tmpstr(0)
If InStr(Agent(1), "NT 5.2") > 0 Then
platform = "Windows 2003"
ElseIf InStr(Agent(1), "Windows CE") > 0 Then
platform = "Windows CE"
ElseIf InStr(Agent(1), "NT 5.1") > 0 Then
platform = "Windows XP"
ElseIf InStr(Agent(1), "NT 4.0") > 0 Then
platform = "Windows NT"
ElseIf InStr(Agent(1), "NT 5.0") > 0 Then
platform = "Windows 2000"
ElseIf InStr(Agent(1), "NT") > 0 Then
platform = "Windows NT"
ElseIf InStr(Agent(1), "9x") > 0 Then
platform = "Windows ME"
ElseIf InStr(Agent(1), "98") > 0 Then
platform = "Windows 98"
ElseIf InStr(Agent(1), "95") > 0 Then
platform = "Windows 95"
ElseIf InStr(Agent(1), "Win32") > 0 Then
platform = "Win32"
ElseIf InStr(Agent(1), "Linux") > 0 Then
platform = "Linux"
ElseIf InStr(Agent(1), "SunOS") > 0 Then
platform = "SunOS"
ElseIf InStr(Agent(1), "Mac") > 0 Then
platform = "Mac"
ElseIf UBound(Agent) > 2 Then
If InStr(Agent(3), "NT 5.1") > 0 Then
platform = "Windows XP"
End If
If InStr(Agent(3), "Linux") > 0 Then
platform = "Linux"
End If
End If
Else
''识别搜索引擎
Dim botlist, i
botlist = "Google,Isaac,Webdup,SurveyBot,Baiduspider,ia_archiver,P.Arthur,FAST-WebCrawler,Java,Microsoft-ATL-Native,TurnitinBot,WebGather,Sleipnir"
botlist = Split(botlist, ",")
For i = 0 To UBound(botlist)
If InStr(Agent, botlist(i)) > 0 Then
platform = botlist(i) & "搜索器"
IsSearch = True
Exit For
End If
Next
End If
If IsSearch Then
Browser = ""
version = ""
Session("SystemInfo_Cls") = Browser & "|||" & version & "|||" & platform & "|||1|||" & AlexaToolbar
Else
Session("SystemInfo_Cls") = Browser & "|||" & version & "|||" & platform & "|||0|||" & AlexaToolbar
End If
End Sub
End Class