function divChg(nu,gr) {

  if (nu==1){
  document.getElementById(gr+'1').background="images/middle_nei_c.jpg";
  document.getElementById(gr+'2').background="images/middle_nei.jpg";
  document.getElementById(gr+'3').background="images/middle_nei.jpg";
  document.getElementById(gr+'4').background="images/middle_nei.jpg";
 
  document.getElementById(gr+'d1').style.display='';
  document.getElementById(gr+'d2').style.display='none';
  document.getElementById(gr+'d3').style.display='none'; 
  document.getElementById(gr+'d4').style.display='none'; 
  }else if(nu==2){
  document.getElementById(gr+'1').background="images/middle_nei.jpg";
  document.getElementById(gr+'2').background="images/middle_nei_c.jpg";
  document.getElementById(gr+'3').background="images/middle_nei.jpg";
  document.getElementById(gr+'4').background="images/middle_nei.jpg";
 
  document.getElementById(gr+'d1').style.display='none';
  document.getElementById(gr+'d2').style.display='';
  document.getElementById(gr+'d3').style.display='none';
  document.getElementById(gr+'d4').style.display='none';

  }else if(nu==3){
  document.getElementById(gr+'1').background="images/middle_nei.jpg";
  document.getElementById(gr+'2').background="images/middle_nei.jpg";
  document.getElementById(gr+'3').background="images/middle_nei_c.jpg";
  document.getElementById(gr+'4').background="images/middle_nei.jpg";
  
  document.getElementById(gr+'d1').style.display='none';
  document.getElementById(gr+'d2').style.display='none';
  document.getElementById(gr+'d3').style.display=''; 
  document.getElementById(gr+'d4').style.display='none'; 
  
  }else if(nu==4){
  document.getElementById(gr+'1').background="images/middle_nei.jpg";
  document.getElementById(gr+'2').background="images/middle_nei.jpg";
  document.getElementById(gr+'3').background="images/middle_nei.jpg";
  document.getElementById(gr+'4').background="images/middle_nei_c.jpg";
  
  document.getElementById(gr+'d1').style.display='none';
  document.getElementById(gr+'d2').style.display='none';
  document.getElementById(gr+'d3').style.display='none'; 
  document.getElementById(gr+'d4').style.display=''; 
  
  }
  
}