1

    <div style="height:100px;width:200px; float:left;background-color:red"> </div> 
    <div style="height:100px; width:200px; float:left;background-color:green"> </div> 
    <div style=" height:100px; width:200px; float:left;background-color:black"> </div> 

注意对div设置宽度和高度，不然显示不出来，div默认没有宽高。

2

    <div style="height:100px;width:200px; display:inline-block;background-color:red;margin-right:20px"> </div> 
    <div style="height:100px; width:200px; display:inline-block;background-color:green;margin-right:20px"> </div> 
    <div style=" height:100px; width:200px; display:inline-block;background-color:black;margin-right:20px"> </div> 

还是给个magin吧，看起来好看点。

3 弹性布局

  <div style="display:flex; ">
    <div style="height:100px;width:200px; background-color:red;margin-right:20px"> </div> 
    <div style="height:100px; width:200px; background-color:green;margin-right:20px"> </div> 
    <div style=" height:100px; width:200px; background-color:black;margin-right:20px"> </div> 
  </div>