function moon_destruction(moonsize,death_star) 
  {
   var destroy_chance;
   
   destroy_chance = (100 - Math.sqrt(moonsize)) * Math.sqrt(death_star);
   destroy_chance = Math.round(destroy_chance * 100) / 100;
   if (destroy_chance > 100) 
     { 
	  destroy_chance = 100; 
	 }
	
   document.getElementById("destroy_chance").innerHTML = destroy_chance;
  }