HTML
/*适用方法1，方法2*/
<body>
<div class="container">
<div class="left"></div>
<div class="middle"></div>
<div class="right"></div>
</div>
</body>
/* 适用方法3：*/
<body>
<div class="container">
<div class="left"></div>
<div class="right"></div>
<div class="middle"></div>
</div>
</body>
CSS
/*方法1：定位实现*/
.container {
position: relative;
}
.left {
position: absolute;
left: 0;
top: 0;
width: 200px;
height: 100px;
background-color: red;
}
.middle {
box-sizing: border-box;
width: 100%;
height: 100px;
padding-left: 200px;
padding-right: 200px;
background-color: blue;
}
.right {
position: absolute;
top: 0;
right: 0;
width: 200px;
height: 100px;
background-color: red;
}
/*方法2：弹性布局实现*/
.container {
display: flex;
}
.left {
flex: 0 0 200px;
height: 100px;
background-color: red;
}
.middle {
width: 100%;
height: 100px;
background-color: blue;
}
.right {
flex: 0 0 200px;
height: 100px;
background-color: red;
}
/*方法3：浮动实现*/
.container {
overflow: hidden;
}
.left {
float: left;
width: 200px;
height: 100px;
background-color: red;
}
.middle {
box-sizing: border-box;
width: 100%;
height: 100px;
padding-left: 200px;
padding-right: 200px;
background-color: blue;
}
.right {
float: right;
width: 200px;
height: 100px;
background-color: red;
}