すぐ忘れてしまうのでメモ
'vbsの場合
dim fso
set fso = createObject("Scripting.FileSystemObject")
msgbox fso.getParentFolderName(WScript.ScriptFullName)
//JScriptの場合
var fso = new ActiveXObject("Scripting.FileSystemObject")
WScript.Echo(fso.getParentFolderName(WScript.ScriptFullName))