<div class="box">
    <div class="left">left</div>
    <div class="right">right</div>
    <div class="center">center</div>
</div>   
//此处注意要先渲染左、右浮动的元素才到中间的元素。元素浮动后剩余兄弟块级元素会占满父元素的宽度
<style>
   .box{
        height:200px;
    }    
    .left{
        float:left;
        width:300px;
    }
    .right{
        float:right;
        width:300px;
    }
</style>

<div class="box">
    <div class="left">left</div>
    <div class="right">right</div>
     <div class="center">center</div>
</div> 
//和浮动布局同理，先渲染左右元素，使其定位在父元素的左右两端，剩余的中间元素占满父元素剩余宽度。
<style>
    .box{
        position: relative;
      }
      .left{
        position: absolute;
        width: 100px;
        left: 0;
      }
      .right{
        width:100px;
        position: absolute;
        right: 0;
      }
      .center{
        margin: 0 100px;
        background: red;
      }
</style>

<div class="box">
  <div class="left">
    left
  </div>
  <div class="center">
    center
  </div>
  <div class="right">
    right
  </div>
</div>
<style>
    .box{
        display: table;
        width: 100%;
      }
      .left{
        display: table-cell;
        width: 100px;
        left: 0;
      }
      .right{
        width:100px;
        display: table-cell;
      }
      .center{
        width: 100%;
        background: red;
      }
</style>

<div class="box">
  <div class="left">
    left
  </div>
  <div class="center">
    center
  </div>
  <div class="right">
    right
  </div>
</div>
<style>
    .box{
        display: flex;
        width: 100%;
      }
      .left{
      
        width: 100px;
        left: 0;
      }
      .right{
        width:100px;
      }
      .center{
        flex:1;
      }
</style>

<div class="box">
  <div class="left">
    left
  </div>
  <div class="center">
    center
  </div>
  <div class="right">
    right
  </div>
</div>
<style>
  .box{
        display: grid;
        grid-template-columns: 100px auto 100px;
        width: 100%;
      }
</style>