var banner=new Array()
banner[0]='<img src="images/coiphatadida-2004.jpg" width="390" height="352">'
banner[1]='<img src="images/Catru-2006.jpg" width="390" height="355">'
banner[2]='<img src="images/oanquan-2009.jpg" width="390" height="405">'
banner[3]='<img src="images/sleeping-2008.jpg" width="390" height="301">'

var whichbanner=Math.floor(Math.random()*(banner.length))
document.write(banner[whichbanner])