<!--
//Re-assign getElementByID to document.all for IE4.0
if(document.all && !document.getElementById) { 
    document.getElementById = function(id) {
         return document.all[id];
    }
}

function disableIt(obj)
{
	obj.disabled = true;
}

function enableIt(obj)
{
	obj.disabled = false;
}

function makecontig (obj) {
 if (obj.checked) { //then the contiguous button is checked
     var butt1 = document.getElementById('button_1');  
     var butt2 = document.getElementById('button_2');  
     var butt3 = document.getElementById('button_3');  
     var butt4 = document.getElementById('button_4');
     var butt5 = document.getElementById('button_5');
     var butt6 = document.getElementById('button_6');
     enableIt (butt1);
     disableIt (butt2);
     disableIt (butt3);
     disableIt (butt4);
     disableIt (butt5);
     disableIt (butt6);
  
 }
 return true;
}

function makesep (obj) {
 if (obj.checked) { //then the separated button is checked
     var butt1 = document.getElementById('button_1');  
     var butt2 = document.getElementById('button_2');  
     var butt3 = document.getElementById('button_3');  
     var butt4 = document.getElementById('button_4');
     var butt5 = document.getElementById('button_5');
     var butt6 = document.getElementById('button_6');
     disableIt (butt1);
     enableIt (butt2);
     enableIt (butt3);
     butt3.focus();
     enableIt (butt4);  
     enableIt (butt5);
     enableIt (butt6);
 }
 return true;
}

function init () {

  if(document.getElementById) {
   var butt_c = document.getElementById('button_c');
   var butt_s = document.getElementById('button_s');

   butt_c.checked=true;
   butt_s.checked=false;
   makecontig (butt_c);
   return true;
  }
}

function which () {

  if(document.getElementById) {
   var butt_c = document.getElementById('button_c');
   var butt_s = document.getElementById('button_s');

   if (butt_c.checked) makecontig (butt_c);
   if (butt_s.checked) makesep (butt_s);
   return true;
  }
}
// -->