一个防止SQL注入函数

<%
function sqlcheck(Str,errtype)
if Instr(LCase(Str),"select ") > 0 or Instr(LCase(Str),"insert ") > 0 or Instr(LCase(Str),"delete ") > 0 or Instr(LCase(Str),"delete from ") > 0 or Instr(LCase(Str),"count(") > 0 or Instr(LCase(Str),"drop table") > 0 or Instr(LCase(Str),"update ") > 0 or Instr(LCase(Str),"truncate ") > 0 or Instr(LCase(Str),"asc(") > 0 or Instr(LCase(Str),"mid(") > 0 or Instr(LCase(Str),"char(") > 0 or Instr(LCase(Str),"xp_cmdshell") > 0 or Instr(LCase(Str),"exec master") > 0 or Instr(LCase(Str),"net localgroup administrators") > 0  or Instr(LCase(Str),"and ") > 0 or Instr(LCase(Str),"net user") > 0 or Instr(LCase(Str),"or ") > 0 then
 Response.write("<script language=javascript>" & vbcrlf & "window.location.href ='ShowError.asp?errtype=" & errtype & "'" & vbcrlf & "</script>")
 Response.End
end if
Str=Replace(Str,"_","")     '过滤SQL注入_
Str=Replace(Str,"*","")     '过滤SQL注入*
Str=Replace(Str," ","")     '过滤SQL注入空格
Str=Replace(Str,chr(34),"")   '过滤SQL注入"
Str=Replace(Str,chr(39),"")            '过滤SQL注入'
Str=Replace(Str,chr(91),"")            '过滤SQL注入[
Str=Replace(Str,chr(93),"")            '过滤SQL注入]
Str=Replace(Str,chr(37),"")            '过滤SQL注入%
Str=Replace(Str,chr(58),"")            '过滤SQL注入:
Str=Replace(Str,chr(59),"")            '过滤SQL注入;
Str=Replace(Str,chr(43),"")            '过滤SQL注入+
Str=Replace(Str,"{","")            '过滤SQL注入{
Str=Replace(Str,"}","")            '过滤SQL注入}
sqlcheck=Str            '返回经过上面字符替换后的Str
end function
%>