小编Ayu*_*rma的帖子

.container{
  border:1px solid;
  padding:1px;
  width:100%;
  margin:1px;
}

.left-item{
  float:left;
  padding:auto;
  margin:1px;
}

.center-item{  
   padding:auto;
  margin:1px;
 }

.right-item{
 float:right;
 padding:auto;
  margin:1px;
}

<div class="container">        
    <button class="left-item">Left</button> <button class="center-item">Center 2</button> <button class="right-item">Right</button> <button class="left-item">Left</button> <button class="right-item">Right</button> <button class="center-item">Center 1</button> <button class="center-item">Center 3</button>        
</div>