var doc=App.ActiveDoc;
var pos=doc.CaretPos;
var txt=doc.GetLineText( pos.Line );
var hd = "## ";
txt=hd + txt.replace(/^\s*#*\s*/g, "");
doc.Delete(pos.Line, 0, pos.Line, 10000000);
doc.Insert( txt );
doc.SetCaretPos( pos.Line, hd.length, true );
