title: Jquery multiple checkboxes with same id issue
body: <p>I have this problem with multiple checkboxes with the samen id (#group) if one of these checkboxes is checked another checkbox with the id (#user) should be checked as well. The problem is that with $this it works like a charm but then again you have also the checkboxes without the #group id. I made this fiddle to demonstrate the problem.</p>
  
  <pre><code>https://jsfiddle.net/njcw9Lav/1/
  </code></pre>
  
  <p>here is the simple Jquery</p>
  
  <pre><code>$('input').on('change', function() {
    var totalSeen = $("input#group:checked").length;
    if ($('#group').prop("checked")) {
      $('#user').prop('checked', true);
      return;
    } else if (totalSeen == 0) {
      $('#user').prop('checked', false);
      return;
    }
  });
  </code></pre>