function rand(id,num) {

   var r=Math.random();
   var randid=0;
   
	
   
   if (r>0 && r<=0.2)
   {
   		randid=1;
   }
   else if (r>0.2 && r<=0.4)
   {
   		randid=2;
   }
   else if (r>0.4 && r<=0.6)
   {
   		randid=3;
   }
   else if (r>0.6 && r<=0.8)
   {
   		randid=4;
   }
   else if (r>0.8 && r<=1)
   {
   		randid=5;
   }
   
   obj=document.getElementById(id+randid).style.display="block";
      
  
}