ASP Special character Filter

Hey, for a long time did not write something, the teacher this time again let me test their own things, found that there is a special character filter lax problem, so again write a function to filter special characters.
Function Chkinvaildword (Words)
Const invaildwords= "select|update|delete|insert|@|--|," ' need to filter characters with ' | ' Separated, the last ending character must be |
Chkinvaildword=true
Invaildword=split (invaildwords, "|")
Inwords=lcase (Trim (Words))
For I=lbound (Invaildword) to UBound (Invaildword)
If Instr (Inwords,invaildword (i)) >0 Then
Chkinvaildword=true
Exit Function
End If
Next
Chkinvaildword=false
End Function
Simpler, the use of the method is not said.
But start with a for each ... next write, but do not know why is not right, so instead of a for loop, feel uncomfortable, but can use!
PS: Today again a headache for a whole day, do not know when the damn headache can be good, otherwise, tomorrow's work I will be crippled! Look forward to a good situation tomorrow! ）