Control number and letter input in ASP

Control recently, friends often ask me how to control the input value in the ASP as in the Javascrip can only be in English or a number, now I sort it out as follows, I'll take the value of the variable string to explain the following:



Method One:
Str=request ("string")
Temp=server.urlencode (str)
If Str=temp Then
Response.Write "You're not typing in English or numbers."
End If



Grammar II:
Str=request ("string")
For I=1 to Len (str)
A=mid (string,i,1)
if ((ASC (a) < "0" and ASC (a) > "9") or (ASC (a) <ASC ("a") and ASC (a) >ASC ("Z")) then
Response.Write "You're not typing in English or numbers."
End If
Next I