Get path of current .jsx file?

You could through and error and catch where.

// Find the location where this script resides
function findScript() {
   var where = "";
   try {
      FORCEERROR = FORCERRROR;
   }
   catch(err) {
      // alert(err.fileName);
      // alert(File(err.fileName).exists);
     where = File(err.fileName);
   }
   return where ;
}