Prevents invalid file source code from being uploaded.

After recent debugging, the code section of the log "how to solve invalid files generated by user uploads" written by the madman in April 12 has been completed. You are welcome to criticize and correct your suggestions for improvement.
[FileName]: upload. asp
[Code]:
<% @ LANGUAGE = "VBSCRIPT" CODEPAGE = "936" %>
<! -- # I nclude virtual = "upload. inc" -->
<%
If Request. ServerVariables ("REQUEST_METHOD") = "POST" then
'Form submission and execution
CONST upFileSize = 100 'file size limit, unit: KB
CONST upFileType = ".gif.jpg.jpeg" 'file type restriction, which can be modified as needed
CONST targetPath = "/publish/images/" 'end with "/" as the path for storing files in the root directory of the website
    
Dim upload, thisFile, formName, iCount
Set upload = new upload_5xSoft '': creates an upload object.
Flag = true' ID of the initial file Upload
For each formName in upload. ifile 'list all parameters of the uploaded file
Set thisFile = upload. ifile (formName) 'to generate a file object
If thisfile. filesize = 0 then
Flag = False
Msg = "select the file you want to upload. "
CALL showErr (Msg)
End if
If thisfile. filesize> upFileSize * 1024 then
Flag = False
Msg = "the file size exceeds the limit. "
CALL showErr (Msg)
End if
If Instr (upFileType, GetExtendName (thisfile. FileName) = 0 then
Flag = False
Msg = "The file format does not meet the requirements. "
CALL showErr (Msg)
End if
     
If Flag then
'Create a temporary Upload folder
TempPath = "/publish/images/" & Session. SessionID &"/"