Convert Active Document File Path to Windows Format

Observe the following lines of code:

#target Photoshop
var joy = app.activeDocument.path;
alert(joy);

Test this when you have some file open in Photoshop.  For example, it outputs something that looks like this:

/d/5)%20Projects/My%20Projects

but I need it to look like this:

D:\5) Projects\My Project

Now, let me make this clear; I need it in EXACTLY the format that I showed immediately above.  I'm working on a Windows machine, and I need to return this filepath in the Windows format for my HTML panel so that the user has easy access to it.  I need it to be just a standard string that includes the spaces and doesn't add in those extra percent signs and twenties.  Unfortunately, I have no idea how to do this.

So the real question here is; how can I obtain the active document's file path in the typical Windows format?