var j=parseInt(Math.random()*3);
  j=(isNaN(j))?0:j;

function writeTopImage(){
  list = new Array();
  list[list.length]='images/Fall10EnrollmentNOW.jpg';
  list[list.length]='images/FallMEHeader-copy.jpg';
  list[list.length]='images/FallSSPHeader-copy.jpg';
  document.write("<img src='"+list[j]+"' border='0' width='536' height='143' />");
}