var imagedisplay = new Array('<img src="pattern/1.gif">','<img src="pattern/2.gif">','<img src="pattern/3.gif">','<img src="pattern/4.gif">','<img src="pattern/5.gif">','<img src="pattern/7.gif">','<img src="pattern/8.gif">','<img src="pattern/9.gif">');
var max = imagedisplay.length;
var num = Math.floor((Math.random() * max));
document.writeln(imagedisplay[num]);