var max=4;
var thisBanner=1;
var banner=new MakeBannerArray(max);

function MakeBannerArray(n)
{
this.length=n;
for (var i=1; i<=n;i++)
{
this[i]="";
}
return this;
} 

banner[1]='<img src="./images/headpic1.jpg" border="0" alt="">';
banner[2]='<img src="./images/headpic2.jpg" border="0" alt="">';
banner[3]='<img src="./images/headpic3.jpg" border="0" alt="">';
banner[4]='<img src="./images/headpic4.jpg" border="0" alt="">';
function rand(n)
{
  rnum=Math.floor(n*Math.random())+1;
  return rnum;
}
  
function setBanner()
{
  thisBanner=rand(max);
}