大众polo功能开关图解:看一下asp代码的意思！

请问这段代码的用在什么场合，才什么情况下调用！！
If FullPath <> "" Then
GetFileName = mid(FullPath,InStrRev(FullPath, "\")+1)
Else
GetFileName = ""
End If
End function
Private function toByte(Str)
dim i,iCode,c,iLow,iHigh
toByte=""
For i=1 To Len(Str)
c=mid(Str,i,1)
iCode =Asc(c)
If iCode<0 Then iCode = iCode + 65535
If iCode>255 Then
iLow = Left(Hex(Asc(c)),2)
iHigh =Right(Hex(Asc(c)),2)
toByte = toByte & chrB("&H"&iLow) & chrB("&H"&iHigh)
Else
toByte = toByte & chrB(AscB(c))
End If
Next
End function
End Class

Class FileInfo
dim FormName,FileName,FilePath,FileSize,FileStart
Private Sub Class_Initialize
FileName = ""
FilePath = ""
FileSize = 0
FileStart= 0
FormName = ""
End Sub

Public function SaveAs(FullPath)
dim dr,ErrorChar,i
SaveAs=1
if trim(fullpath)="" or FileSize=0 or FileStart=0 or FileName="" then exit function
if FileStart=0 or right(fullpath,1)="/" then exit function
set dr=CreateObject("Adodb.Stream")
dr.Mode=3
dr.Type=1