// JavaScript Document<script type="text/javascript"> 
function chooseStyle() {
  var css = new Array('body1','body2','body3','body4','body5');
  var i = Math.floor(Math.random()*css.length);
  var style = "css/"+css[i]+".css";
  
  return style;
}
 
document.write('<link rel="stylesheet" href="'+chooseStyle()+'" type="text/css" />');