I wrote some functions including UTF-8 conversion   Func _URIEncode($sData)
    ; Prog@ndy
    Local $aData = StringSplit(BinaryToString(StringToBinary($sData,4),1),"")
    Local $nChar
    $sData=""
    For $i = 1 To $aData[0]
        ; ConsoleWrite($aData[$i] & @CRLF)
        $nChar = Asc($aData[$i])
        Switch $nChar
            Case 45, 46, 48 To 57, 65 To 90, 95, 97 To 122, 126
                $sData &= $aData[$i]
            Case 32
                $sData &= "+"
            Case Else
                $sData &= "%" & Hex($nChar,2)
        EndSwitch
    Next
    Return $sData
EndFunc
Func _URIDecode($sData)
    ; Prog@ndy
    Local $aData = StringSplit(StringReplace($sData,"+"," ",0,1),"%")
    $sData = ""
    For $i = 2 To $aData[0]
        $aData[1] &= Chr(Dec(StringLeft($aData[$i],2))) & StringTrimLeft($aData[$i],2)
    Next
    Return BinaryToString(StringToBinary($aData[1],1),4)
EndFunc
MsgBox(0, '', _URIDecode(_URIEncode("testäöü fv"))) Edit 2012: Fixed bug in _URIEncode, removed debug output