var banner=new Array()

banner[0]='<img border="0" src="zad.jpg" >'
banner[1]='<img border="0" src="zad2.jpg" >'
banner[2]='<img border="0" src="zad3.jpg" >'
banner[3]='<img border="0" src="zad10.jpg" >'
banner[4]='<img border="0" src="zad4.jpg" >'
var whichbanner=Math.floor(Math.random()*(banner.length))
document.write(banner[whichbanner])