(Information and examples taken from the DroidScript documentation)

Checks if folder is a file or folder. Returns “true” or “false” values.

app.IsFolder( folder );

app.ShowPopup( "/sdcard/DroidScript is a Folder: " + 
  app.IsFolder( "/sdcard/DroidScript" ) + 
  "\n/sdcard/DroidScript/index.html is a Folder: " + 
  app.IsFolder( "/sdcard/DroidScript/index.html" ) );