Get name of the folder after parent.

Hi forum.

I need a great help from you.

If I could get the name of the folder which is between the Desktop and the indesign files where it ls saved...

eg.

/Users/wleastudio/Desktop/rantac/acb.indd.

I need to get the folder name highlited in red and alert...

if this is straight away on desktop i can do alert easily like below..

name = Folder("/Users/wleastudio/Desktop/");

if(app.activeDocument.filePath == name.path+"/" + name.name) {

    alert ("The document is in Desktop"), exit;

    }

if, the document is saved inside a folder on a desktop, that's the problem, i'm finding to difficult to find folder name and get alert..

/Users/wleastudio/Desktop/rantac/acb.indd.

Many thanks in advance