bottom

【2】float + absolute + (fix)

通過增加結(jié)構(gòu)來提高兼容性，.middle元素設置100%的高度，.top和.bottom設置absolute覆蓋在.middle上

    
        
top
      
    
        
            
                
left
            
            
                
                    
right
                
            
                
     
    
        
bottom
            

思路二: inline-block

【1】inline-block + calc

    
        
top
      
    
        
            
left
        
        
            
                
right
            
        
            
    
        
bottom
            

【2】inline-block + absolute + (fix)

    
        
top
      
    
        
            
                
left
            
            
                
                    
                        
right
                    
                                
            
                 
    
    
        
bottom
            

思路三: table

　　水平方向子元素的間距可以用border實現(xiàn)。所有瀏覽器都不支持給table-cell元素設置overflow屬性。firefox和IE11瀏覽器不支持給table-cell元素的設置100%高度的子元素設置overflow屬性

    
        
top
     
    
        
            
                
left
                 
            
                
                    
                        
right
                                
                                    
               
                 
        
    
        
bottom
            

思路四: absolute

    
        
top
     
    
        
            
left
             
        
            
                
right
                        
                            
                  
    
        
bottom
            

思路五: flex

flex常用于小范圍的布局，使用全屏布局時會因為性能問題，出現(xiàn)卡頓現(xiàn)象。如果要使用全屏自適應布局，則只有flex才能達到效果

    
        
top
     
    
        
            
left
             
        
            
                
right
                        
                            
                  
    
        
bottom