$(window).load(function(){
  for( forum=1; forum<=3; forum++) {
    for( lecture=1; lecture<=4; lecture++ ) {
      if( $('#forum-'+forum+'-'+lecture).attr('checked') ) 
        $('#forum-hidden-'+forum+'-'+lecture).attr('value', 'x');
      else
        $('#forum-hidden-'+forum+'-'+lecture).removeAttr('value');
    }
  }
  
  $('#forum-1-1').bind('click', function(){ setHiddenForumValue(1,1) });
  $('#forum-1-2').bind('click', function(){ setHiddenForumValue(1,2) });
  $('#forum-1-3').bind('click', function(){ setHiddenForumValue(1,3) });
  $('#forum-1-4').bind('click', function(){ setHiddenForumValue(1,4) });
  $('#forum-2-1').bind('click', function(){ setHiddenForumValue(2,1) });
  $('#forum-2-2').bind('click', function(){ setHiddenForumValue(2,2) });
  $('#forum-2-3').bind('click', function(){ setHiddenForumValue(2,3) });
  $('#forum-2-4').bind('click', function(){ setHiddenForumValue(2,4) });
  $('#forum-3-1').bind('click', function(){ setHiddenForumValue(3,1) });
  $('#forum-3-2').bind('click', function(){ setHiddenForumValue(3,2) });
  $('#forum-3-3').bind('click', function(){ setHiddenForumValue(3,3) });
  $('#forum-3-4').bind('click', function(){ setHiddenForumValue(3,4) });
  
});

function setHiddenForumValue(forum,lecture) {
  var i=1;
  while( document.getElementById("forum-hidden-" + forum + "-" + i) ) {
    if(i == lecture)
      $('#forum-hidden-' + forum + '-' + i).attr('value', 'x');
    else
      $('#forum-hidden-' + forum + '-' + i).removeAttr('value');
    i++;
  }
}