var myRectangle = app.selection[0]; 
var myScaleMatrix = app.transformationMatrices.add({horizontalScaleFactor:.5, verticalScaleFactor:.5}); 
myRectangle.transform(CoordinateSpaces.pasteboardCoordinates, app.layoutWindows[0].transformReferencePoint, myScaleMatrix); 

if (app.selection.length > 0 && app.selection[0].constructor.name  == 'Rectangle') { 
	var myScale = 50; 
	with (app.selection[0]) { 
		horizontalScale = myScale; 
		verticalScale = myScale;     
		fit(FitOptions.frameToContent);    
	}   
}