URL decoding function, simple and easy to understand. The main reason is that the original Chinese has been URL encoded. When it is used specifically, it needs to be restored to Chinese, so such a function is needed. For example:
When we search for Script Home in Baidu, the parameters after the URL are
http://www.baidu.com/s?cl=3&wd=%BD%C5%B1%BE%D6%AE%BC%D2
If we want to restore %BD%C5%B1%BE%D6%AE%BC%D2 to Chinese, just use the following function.
<%
response.write urldecode(http://www.baidu.com/s?cl=3&wd=%BD%C5%B1%BE%D6%AE%BC%D2)
'================================================
'Function name: URLDecode
'Function: URL decoding
'================================================
Function URLDecode(ByVal urlcode)
Dim start,final,length,char,i,butf8,pass
Dim leftstr,rightstr,finalstr
Dim b0,b1,bx,blength,position,u,utf8
On Error Resume Next
b0 = Array(192,224,240,248,252,254)
urlcode = Replace(urlcode,+, )
pass = 0
utf8 = -1
length = Len(urlcode) : start = InStr(urlcode,%) : final = InStrRev(urlcode,%)
If start = 0 Or length < 3 Then URLDecode = urlcode : Exit Function
leftstr = Left(urlcode,start - 1) : rightstr = Right(urlcode,length - 2 - final)
For i = start To final
char = Mid(urlcode,i,1)
If char = %Then
bx = URLDecode_Hex(Mid(urlcode,i + 1,2))
If bx > 31 And bx < 128 Then
i = i + 2
finalstr = finalstr & ChrW(bx)
ElseIf bx > 127 Then
i = i + 2
If utf8 < 0 Then
butf8 = 1 : blength = -1 : b1 = bx
For position = 4 To 0 Step -1
If b1 >= b0(position) And b1 < b0(position + 1) Then
blength = position
Exit For
End If
Next
If blength > -1 Then
For position = 0 To blength
b1 = URLDecode_Hex(Mid(urlcode,i + position * 3 + 2,2))
If b1 < 128 Or b1 > 191 Then butf8 = 0 : Exit For
Next
Else
butf8 = 0
End If
If butf8 = 1 And blength = 0 Then butf8 = -2
If butf8 > -1 And utf8 = -2 Then i = start - 1 : finalstr = : pass = 1
utf8 = butf8
End If
If pass = 0 Then
If utf8 = 1 Then
b1 = bx : u = 0 : blength = -1
For position = 4 To 0 Step -1
If b1 >= b0(position) And b1 < b0(position + 1) Then
blength = position
b1 = (b1 xOr b0(position)) * 64 ^ (position + 1)
Exit For
End If
Next
If blength > -1 Then
For position = 0 To blength
bx = URLDecode_Hex(Mid(urlcode,i + 2,2)) : i = i + 3
If bx < 128 Or bx > 191 Then u = 0 : Exit For
u = u + (bx And 63) * 64 ^ (blength - position)
Next
If u > 0 Then finalstr = finalstr & ChrW(b1 + u)
End If
Else
b1 = bx * &h100 : u = 0
bx = URLDecode_Hex(Mid(urlcode,i + 2,2))
If bx > 0 Then
u = b1 + bx
i = i + 3
Else
If Left(urlcode,1) = % Then
u = b1 + Asc(Mid(urlcode,i + 3,1))
i = i + 2
Else
u = b1 + Asc(Mid(urlcode,i + 1,1))
i = i + 1
End If
End If
finalstr = finalstr & Chr(u)
End If
Else
pass = 0
End If
End If
Else
finalstr = finalstr & char
End If
Next
URLDecode = leftstr & finalstr & rightstr
End Function
Function URLDecode_Hex(ByVal h)
On Error Resume Next
h = &h & Trim(h) : URLDecode_Hex = -1
If Len(h) <> 4 Then Exit Function
If isNumeric(h) Then URLDecode_Hex = cInt(h)
End Function
%>