三栏布局-左右宽固定,中间自适应

常用方式罗列

• float
• absolute
• table
• flex
• grid

float

    <div class="container">
        <div class="left">left</div>
        <div class="right">right</div>
        <div class="center">center</div>
    </div>

.container {
    overflow: auto;  
}
.left {
    width: 200px;
    float: left;
    background-color: #1ABC9C;
}
.right {
    width: 200px;
    float: right;
    background-color: #2ECC71;
}
.center {
    margin-left: 200px;
    margin-right: 200px;
    background-color: #3498DB;
}

上面实现方式优点,实现简单兼容性好

缺点：根据渲染的规则,从上到下,也就是说left和right会优先渲染, center部分会最后渲染.

优化方式-1

利用负margin来完成

<div class="container">
    <div class="center">
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
    </div>
    <div class="left">left</div>
    <div class="right">right</div>
</div>

.container {
    overflow: auto;  
}
.left,
.right,
.center {
    box-sizing: border-box;
}
.left {
    width: 200px;
    float: left;
    background-color: #1ABC9C;
    margin-left: -100%;
}
.right {
    width: 200px;
    float: right;  // float:left;
    background-color: #2ECC71;
    margin-left: -200px;
}
.center {
    float: left;
    width: 100%;
    padding-left: 200px;
    padding-right: 200px;
    background-color: #3498DB;

}

完成前面主要内容优先加载问题,但是又有新问题,当主体内容过长的时,发现背景(边框、背景图等等)影响到了两侧

如果只处理背景问题可以使用下面方式

    .center {
        background-clip:  content-box
    }

如果有边框、背景图片等显然上面不能满足。

优化方式二 (圣杯布局)

<div class="container">
    <div class="center">
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
    </div>
    <div class="left">left</div>
    <div class="right">right</div>
</div>

.container {
    margin:0 200px;
    position: relative;
}
.left,
.right,
.center {
    box-sizing: border-box;
}

.center {
    float: left;
    width: 100%;
    background-color: #3498DB;
}
.left {
    position: relative;
    left:-200px;
    float: left;
    width: 200px;
    margin-left: -100%;
    background-color: #1ABC9C;
}

.right {
    position: relative;
    right:-200px;
    float: right;
    width: 200px;
    margin-left: -200px;
    background-color: #2ECC71;
}

优化方式三: (双飞翼布局) 给 center 元素包裹一个容器

    <div class="container">
        <div class="center-warpper">
            <div class="center">
                <p>center</p>
                <p>center</p>
                <p>center</p>
                <p>center</p>
                <p>center</p>
                <p>center</p>
                <p>center</p>
            </div>
        </div>
        <div class="left">left</div>
        <div class="right">right</div>
    </div>

.container {
    overflow: auto;
}

.left,
.right,
.center,
.center-warpper {
    box-sizing: border-box;
}
.center-warpper {
    float:left;
    width: 100%;
    padding-left: 200px;
    padding-right: 200px;
}
.center {
    width: 100%;
    overflow: auto;
    background-color: #3498DB;
}
.left {
    width: 200px;
    float: left;
    background-color: #1ABC9C;
    margin-left: -100%;
}

.right {
    width: 200px;
    float: right;
    background-color: #2ECC71;
    margin-left: -200px;
}

处理方式二和三解决方式非常类似,只是处理的细节不一样. 具体用那个都可以一般推荐用前者

absolute

 <div class="container">
    <div class="center">
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
    </div>
    <div class="left">left</div>
    <div class="right">right</div>
</div>

.container {
    position: relative;
}

.left,
.right,
.center {
    box-sizing: border-box;
}
.center {
    position: absolute;
    left: 200px;
    right: 200px;
    background-color: #3498DB;
}
.left {
    position: absolute;
    left: 0;
    width: 200px;
    background-color: #1ABC9C;
}
.right {
    position: absolute;
    right: 0;
    float: right;
    width: 200px;
    background-color: #2ECC71;
}

table

     <div class="container">
        <div class="left">left</div>
        <div class="center">
            <p>center</p>
            <p>center</p>
            <p>center</p>
            <p>center</p>
            <p>center</p>
            <p>center</p>
            <p>center</p>
        </div>
        <div class="right">right</div>
    </div>

.container {
    position: relative;
    display: table;
    width: 100%;
}

.left,
.right,
.center {
    box-sizing: border-box;
    display: table-cell;
}
.center {
    background-color: #3498DB;
}
.left {
    width: 200px;
    background-color: #1ABC9C;
}

.right {
    width: 200px;
    background-color: #2ECC71;
}

flex

<div class="container">
    <div class="left">left</div>
    <div class="center">
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
    </div>
    <div class="right">right</div>
</div>

.container {
    position: relative;
    display: flex;
    width: 100%;
}

.left,
.right,
.center {
    box-sizing: border-box;
    display: table-cell;
}

.center {
    background-color: #3498DB;
    flex:1;
}

.left {
    width: 200px;
    background-color: #1ABC9C;
}

.right {
    width: 200px;
    background-color: #2ECC71;
}

Grid

 <div class="container">
    <div class="left">left</div>
    <div class="center">
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
        <p>center</p>
    </div>
    <div class="right">right</div>
</div>

.container {
    position: relative;
    display: grid;
    width: 100%;
    grid-template-columns: 200px auto 200px;
}

.left,
.right,
.center {
    box-sizing: border-box;
}

.center {
    background-color: #3498DB;
}

.left {
    background-color: #1ABC9C;
}

.right {
    background-color: #2ECC71;
}

上面就是实现的几种方式, 细心同学应该可以看到 float、absoulut 这两种方式左右两列并不会随着中间内容区域高度变化而变化。

如果想要创建三列布局中间自适应，且三列都等高的话选择 table、flex、Grid;

具体兼容可查阅 兼容性查看

如果有更好的方式，大家可以在评论区给出; 一起讨论学习