用样式怎么去掉标签之间换行的间距

这样写span之间没有间距
<div>
  <span>1</span><span>2</span><span>3</span>
</div>

这样写换行了span之间有间距
<div>
  <span>1</span>
  <span>2</span>
  <span>3</span>
</div>

---

span{
            display: block;
            float:left;
        }

---

div{font-size: 0;}
span{font-size: 12px;}