var pic = 1; 
var link = 1; 
var numpics = 1; 
day = new Date(); 
seed = day.getTime(); 
ran = parseInt(((seed - (parseInt(seed/1000,10) * 1000))/10)/100*numpics + 1,10); 

if (ran == (1)) 
{pic=("images/advertising_spacer.gif");link=("")}

if (ran == (2)) 
{pic=("images/banner/PTC_2012_Banner-468x60.jpg");link=("http://www.ptc.org")} 



document.write("<a href=\"" + link + "\" target=\"_blank\"><IMG SRC=\"" + pic + "\" WIDTH=\"468\" HEIGHT=\"60\" BORDER=\"0\"></a>")