URL Encode and Decode for Classic ASP

URLDecode
For some reason, Microsoft did not include a URL decode function with Active Server Pages. Most likely, this was because the decoding of querystring variables is done automatically for you when you access the querystring object:


' -----------------------------------------
' URL decode to retrieve the original value

Function URLDecode(sConvert)
Dim aSplit
Dim sOutput
Dim I
If IsNull(sConvert) Then
URLDecode = ""
Exit Function
End If

' convert all pluses to spaces
sOutput = REPLACE(sConvert, "+", " ")

' next convert %hexdigits to the character
aSplit = Split(sOutput, "%")

If IsArray(aSplit) Then
sOutput = aSplit(0)
For I = 0 to UBound(aSplit) - 1
sOutput = sOutput & _
Chr("&H" & Left(aSplit(i + 1), 2)) &_
Right(aSplit(i + 1), Len(aSplit(i + 1)) - 2)
Next
End If

URLDecode = sOutput
End Function


Server.HTMLEncode
This useful built-in function is very useful for encoding text that should be displayed in a form input. By "form input" we mean a web form control such as a text input, select or textarea control.

You may have noticed that certain characters cause the HTML on your web form to be interpretted incorrectly. Specifically, the HTML tag characters "<" and ">" can have this effect as well as the quote character (") which is used to encapsulate values.

Server.HTMLEncode(sValue)

HTMLDecode
Just like with the URLDecode function described previously, Microsoft, in its infinite wisdom decided not to include an HTMLDecode function with their Server component. It is a relatively simple matter to decode this test data (although I haven't had a need to do this so far.) For completeness sake, here is an HTMLDecode function you may use:

Function HTMLDecode(sText)
Dim I
sText = Replace(sText, """, Chr(34))
sText = Replace(sText, "<" , Chr(60))
sText = Replace(sText, ">" , Chr(62))
sText = Replace(sText, "&" , Chr(38))
sText = Replace(sText, " ", Chr(32))
For I = 1 to 255
sText = Replace(sText, "&#" & I & ";", Chr(I))
Next
HTMLDecode = sText
End Function