var anzahl = 5 ;
	var nummer = Math.random() ;
	var txt = Math.round( (anzahl-1) *  nummer) + 1 ;
	text = new Array
	text[1] = "image1.jpg";
	text[2] = "image2.jpg";
	text[3] = "image3.jpg";
	text[4] = "image4.jpg";
	text[5] = "image5.jpg";
	var bg = text[txt];