[Indesign] Fill Blank Cells

gistfile1.js

var oCells = app.documents[0].stories.everyItem().tables.everyItem().cells.everyItem().getElements(),
	len = oCells.length,
	i = 0;
for (; i < len; i ++){ 
	oCells[i].contents == "" && oCells[i].contents = "-";
}