// a function to get the value of a cookie by name
function getCookie ( cookieName ) {
  var results = document.cookie.match ( '(^|;) ?' + cookieName + '=([^;]*)(;|$)' );
 
  if ( results ) {
    return ( unescape ( results[2] ) );
  }
  else {
    return null;
  }
}

<script type="text/javascript" charset="utf-8">
  $(document).ready(function() {
 
    function minShown(minAllowed) {
 
      // Interrupt next/submit function
      $('form#limesurvey').submit(function(){
 
        var visible = $('.multiple-opt input.checkbox').length - $('.multiple-opt input.checkbox:checked').length;
 
        // If less than the minimum, clear the question and move on
        if(visible < minAllowed) {
          document.cookie = 'lsSkipQ = 1';
        }
        else {
          document.cookie = 'lsSkipQ = 0';
        }
 
        // Carry on with submit
        return true;
      });
    }
 
    minShown(3);
 
  });
 
</script>

<script type="text/javascript" charset="utf-8">
  $(document).ready(function() {
 
    // Retrieve the cookie
    var skip = getCookie ('lsSkipQ');
 
    // If we're supposed to skip, uncheck all options and move on
    if(skip > 0) {
      $('.list-radio').hide();
      $('.list-radio input,radio').attr('checked', false);
      document.limesurvey.move.value = 'movenext';
      document.limesurvey.submit();
    }
 
  });
 
</script>

<script type="text/javascript" charset="utf-8">
  $(document).ready(function() {
 
    // Retrieve the cookie
    var skip = getCookie ('lsSkipQ');
 
    // Skip previous question
    if(skip > 0) {
      $('#moveprevbtn').mousedown(function () { 
        $('#thisstep').val($('#thisstep').val() - 1);
      });
    }
 
  });
 
</script>