判断访问是否来自搜索引擎的函数

<%
'是否真正的搜索引擎
Function IsWebSearch()
	IsWebSearch = False
	Dim Botlist,i
	BotList = "Google,Isaac,SurveyBot,Baiduspider,yahoo,yisou,3721,ia_archiver,P.Arthur,FAST-WebCrawler,Java,Microsoft-ATL-Native,TurnitinBot,WebGather,Sleipnir"
	Botlist = Split(Botlist,",")
	For i = 0 To Ubound(Botlist)
		If InStr(Lcase(Request.ServerVariables("HTTP_USER_AGENT")),Lcase(Botlist(i))) > 0 Then
			IsWebSearch = True
			Exit For
		End If
	Next
End Function
%>