<div class="btn-group" data-toggle="buttons-radio">

  <button id="fs_8"  type="button" class="btn btn-mini">8px</button>

  <button id="fs_9"  type="button" class="btn btn-mini">9px</button>

  <button id="fs_10" type="button" class="btn btn-mini">10px</button>

  <button id="fs_11" type="button" class="btn btn-mini">11px</button>

  <button id="fs_12" type="button" class="btn btn-mini active">12px</button>

  <button id="fs_13" type="button" class="btn btn-mini">13px</button>

  <button id="fs_14" type="button" class="btn btn-mini">14px</button>

</div><br/>