CSS全屏布局的6种方式

　　全屏布局在实际工作中是很常用的，比如管理系统、监控平台等。本文将介绍关于全屏布局的6种思路

float

【1】float + calc

　　通过calc()函数计算出.middle元素的高度，并设置子元素高度为100%

<style>
body,p{margin: 0;}
body,html,.parent{height: 100%;}
.middle{
    overflow: hidden;
    height: calc(100% - 100px);
}
.left{
    float: left;
    width: 100px;
    margin-right: 20px;
    height: 100%;
}
.right{
    overflow: auto;
    height: 100%;
}
.right-in{
    height: 1000px;
}
.top,.bottom{height:50px;}
</style>

<div class="parent" id="parent" style="background-color: lightgrey;">
    <div class="top" style="background-color: lightblue;">
        <p>top</p>
    </div>  
    <div class="middle" style="background-color: pink;">
        <div class="left" style="background-color: orange;">
            <p>left</p>
        </div>
        <div class="right" style="background-color: lightsalmon;">
            <div class="right-in">
                <p>right</p>
            </div>
        </div>
    </div>          
    <div class="bottom" style="background-color: lightgreen;">
        <p>bottom</p>
    </div>        
</div>

【2】float + absolute + (fix)

　　通过增加结构来提高兼容性，.middle元素设置100%的高度，.top和.bottom设置absolute覆盖在.middle上

<style>
body,p{margin: 0;}
body,html,.parent{height: 100%;}
.top,.bottom{
    position: absolute;
    height:50px;
    left: 0;
    right: 0;
}
.top{top: 0;}
.bottom{bottom: 0;}
.middleWrap{
    height: 100%;
    overflow: hidden;
}
.middle{
    overflow: hidden;
    height: 100%;
    margin: 50px 0;
}
.left{
    float: left;
    width: 100px;
    margin-right: 20px;
    height: 100%;
}
.right{
    overflow: auto;
    height: 100%;
}
.right-in{
    height: 1000px;
}
</style>

<div class="parent" id="parent" style="background-color: lightgrey;">
    <div class="top" style="background-color: lightblue;">
        <p>top</p>
    </div>  
    <div class="middleWrap">
        <div class="middle" style="background-color: pink;">
            <div class="left" style="background-color: orange;">
                <p>left</p>
            </div>
            <div class="right" style="background-color: lightsalmon;">
                <div class="right-in">
                    <p>right</p>
                </div>
            </div>
        </div>        
    </div> 
    <div class="bottom" style="background-color: lightgreen;">
        <p>bottom</p>
    </div>        
</div>

inline-block

【1】inline-block + calc

<style>
body,p{margin: 0;}
body,html,.parent{height: 100%;}
.middle{
    height: calc(100% - 100px);
    font-size: 0;
}
.left,.right{
    display: inline-block;
    vertical-align: top;
    font-size: 16px;
}
.left{
    width: 100px;
    margin-right: 20px;
    height: 100%;
}
.right{
    width: calc(100% - 120px);
    height: 100%;
    overflow: auto;
}
.right-in{
    height: 1000px;
}
.top,.bottom{height: 50px;}
</style>

<div class="parent" id="parent" style="background-color: lightgrey;">
    <div class="top" style="background-color: lightblue;">
        <p>top</p>
    </div>  
    <div class="middle" style="background-color: pink;">
        <div class="left" style="background-color: orange;">
            <p>left</p>
        </div>
        <div class="right" style="background-color: lightsalmon;">
            <div class="right-in">
                <p>right</p>
            </div>
        </div>
    </div>        
    <div class="bottom" style="background-color: lightgreen;">
        <p>bottom</p>
    </div>        
</div>

【2】inline-block + absolute + (fix)

<style>
body,p{margin: 0;}
body,html,.parent{height: 100%;}
.top,.bottom{
    position: absolute;
    left: 0;
    right: 0;
    height: 50px;
}
.top{top: 0;}
.bottom{bottom: 0;}
.middleWrap{
    height: 100%;
    font-size: 0;
    overflow: hidden;
}
.middle{
    position: relative;
    height: 100%;
    margin: 50px 0;
    overflow: hidden;
}
.left,.rightWrap{
    display: inline-block;
    vertical-align: top;
    font-size: 16px;
}
.left{
    position: absolute;
    width: 100px;
    margin-right: 20px;
    height: 100%;
}
.rightWrap{
    width: 100%;
    height: 100%;
}
.right{
    height: 100%;
    margin-left: 120px;
    overflow: auto;
}
.right-in{
    height: 1000px;
}
</style>

<div class="parent" id="parent" style="background-color: lightgrey;">
    <div class="top" style="background-color: lightblue;">
        <p>top</p>
    </div>  
    <div class="middleWrap">
        <div class="middle" style="background-color: pink;">
            <div class="left" style="background-color: orange;">
                <p>left</p>
            </div>
            <div class="rightWrap">
                <div class="right" style="background-color: lightsalmon;">
                    <div class="right-in">
                        <p>right</p>
                    </div>
                </div>                
            </div>
        </div>         
    </div>
    <div class="bottom" style="background-color: lightgreen;">
        <p>bottom</p>
    </div>        
</div>

table

　　水平方向子元素的间距可以用border实现。所有浏览器都不支持给table-cell元素设置overflow属性。firefox和IE11浏览器不支持给table-cell元素的设置100%高度的子元素设置overflow属性

<style>
body,p{margin: 0;}
body,html,.parent{height: 100%;}
.top,.bottom{
    position: absolute;
    width: 100%;
    height: 50px;
}
.bottom{bottom: 0;}
.middleWrap{
    height: 100%;
    overflow: hidden;
}
.middle{
    width: 100%;
    height: 100%;
    display: table;    
    margin: 50px 0;
    table-layout: fixed;
}
.left{
    display: table-cell;
    width: 120px;
    border-right: 20px solid lightgray;
}
.rightWrap{
    display: table-cell;
    height: 100%;
}
.right{
    height: 100%;
    overflow: auto;
}
.right-in{
    height: 1000px;
}
</style>

<div class="parent" id="parent" style="background-color: lightgrey;">
    <div class="top" style="background-color: lightblue;">
        <p>top</p>
    </div> 
    <div class="middleWrap">
        <div class="middle" style="background-color: pink;">
            <div class="left" style="background-color: orange;">
                <p>left</p>
            </div>     
            <div class="rightWrap">
                <div class="right" style="background-color: lightsalmon;">
                    <div class="right-in">
                        <p>right</p>
                    </div>            
                </div>                    
            </div>   
        </div>         
    </div>    
    <div class="bottom" style="background-color: lightgreen;">
        <p>bottom</p>
    </div>        
</div>

absolute

<style>
body,p{margin: 0;}
body,html,.parent{height: 100%;}
.top,.middle,.bottom{
    position: absolute;
    left: 0;
    right: 0;
}
.top{
    top: 0;
    height: 50px;
}
.bottom{
    bottom: 0;
    height: 50px;
}
.middle{
    top: 50px;
    bottom: 50px;
}
.left,.right{
    position: absolute;
    top: 0;
    bottom: 0;
}
.left{
    width:100px;
}
.right{
    left: 120px;
    right: 0;
    overflow: auto;
}
.right-in{
    height: 1000px;
}
</style>

<div class="parent" id="parent" style="background-color: lightgrey;">
    <div class="top" style="background-color: lightblue;">
        <p>top</p>
    </div> 
    <div class="middle" style="background-color: pink;">
        <div class="left" style="background-color: orange;">
            <p>left</p>
        </div>     
        <div class="right" style="background-color: lightsalmon;">
            <div class="right-in">
                <p>right</p>
            </div>            
        </div>                    
    </div>              
    <div class="bottom" style="background-color: lightgreen;">
        <p>bottom</p>
    </div>        
</div>

flex

　　flex常用于小范围的布局，使用全屏布局时会因为性能问题，出现卡顿现象。如果要使用全屏自适应布局，则只有flex才能达到效果

<style>
body,p{margin: 0;}
body,html,.parent{height: 100%;}
.parent{
    display: flex;
    flex-direction: column;
}
.top,.bottom{
    height: 50px;
}
.middle{
    display: flex;
    flex: 1;
}
.left{
    width: 100px;
    margin-right: 20px;
}
.right{
    flex: 1;
    overflow: auto;
}
.right-in{
    height: 1000px;
}
</style>

<div class="parent" id="parent" style="background-color: lightgrey;">
    <div class="top" style="background-color: lightblue;">
        <p>top</p>
    </div> 
    <div class="middle" style="background-color: pink;">
        <div class="left" style="background-color: orange;">
            <p>left</p>
        </div>     
        <div class="right" style="background-color: lightsalmon;">
            <div class="right-in">
                <p>right</p>
            </div>            
        </div>                    
    </div>              
    <div class="bottom" style="background-color: lightgreen;">
        <p>bottom</p>
    </div>        
</div>

grid

<style>
body,p{margin: 0;}
body,html,.parent{height: 100%;}
.parent{
    display: grid;
    grid-template-rows:50px auto 50px;
}
.middle{
    overflow:hidden;
    display:grid;
    grid-template-columns: 100px 1fr;
    grid-gap:20px;
}
.right{
    overflow:auto;
}
.right-in{
    height: 1000px;
}
</style>

<div class="parent" id="parent" style="background-color: lightgrey;">
    <div class="top" style="background-color: lightblue;">
        <p>top</p>
    </div> 
    <div class="middle" style="background-color: pink;">
        <div class="left" style="background-color: orange;">
            <p>left</p>
        </div>     
        <div class="right" style="background-color: lightsalmon;">
            <div class="right-in">
                <p>right</p>
            </div>            
        </div>                    
    </div>              
    <div class="bottom" style="background-color: lightgreen;">
        <p>bottom</p>
    </div>        
</div>

总结

　　全屏布局实际上就是两列或三列自适应布局的扩展形式。由于实现的是全屏效果，高度实际上是固定的，所以思路并没有等高布局局限。水平方向元素之间的间距根据实际情况使用margin、padding、border都可以实现

全屏布局