absolute的元素不会占据未浮动的元素的空间
<html> <head> <style type="text/css"> .flipbox{ width: 500px; height:500px; position: relative; } .sidea{ height: 400px; width:500px; background: green; } .sideb{ width: 100%; height: 100%; position: absolute; background: blue; } </style> </head> <body> <div class="flipbox"> <div class="sidea">side a</div> <div class="sideb">side b</div> </div> </body> </html>
