<div class="row-fluid">
    <div class="span12">
        <button class="hided" style="margin-left:3px;float:left;"></button>
        <button class="showed" style="display:none;margin-left:3px;float:left;"></button>
        <button class="hided" style="margin-right:10px;float:right;"></button>
        <button class="showed" style="display:none;margin-right:10px;float:right;"></button>
    </div>
</div>