function buttonclick(form,correct,number)
{
   var rightlayer = "right"+number;
   var wronglayer = "wrong"+number;
   var answer = "";
   var correctanswer = "";

   for(x=0;x<=correct.length;x++)
   {      
       if(correct.charAt(x) != ",")
       {
          correctanswer = correctanswer+correct.charAt(x);
       }
   }

   for(x=0;x<5;x++)
   {
       if(form.elements[x].checked == true)
       {
          answer = answer+form.elements[x].value;
       }
   }

   if(answer == "")
   {
      return;
   }
  
   if(document.layers)
   {
      if (answer == correctanswer)
      {
         document.layers[rightlayer].className="respon";
         document.layers[wronglayer].className="respoff";
      }
      else
      {     
         document.layers[rightlayer].className="respoff";
         document.layers[wronglayer].className="respon";
      }
   }
   else if (document.all)
   {
      if (answer == correctanswer)
      {
         document.all[rightlayer].className="respon";
         document.all[wronglayer].className="respoff";
      }
      else
      {
         document.all[rightlayer].className="respoff";
         document.all[wronglayer].className="respon";
      }
   }
   else
   {
      if (answer == correctanswer)
      {
         document.getElementById(rightlayer).className="respon";
         document.getElementById(wronglayer).className="respoff";
      }
      else
      {
         document.getElementById(rightlayer).className="respoff";
         document.getElementById(wronglayer).className="respon";
      }
   }   
}