function rotate(){
   var page=Math.floor(1+Math.random()*5)
   switch (page){
      case 1:
         self.location="feature1.html";
	     break;
      case 2:
         self.location="feature2.html";
	     break;
      case 3:
         self.location="feature3.html";
	     break;
      case 4:
        self.location="feature4.html";
	     break;
      case 5:
         self.location="feature5.html";
	     break; 
	}
}