<!DOCTYPE HTML> <html lang="en-US"> <head> <meta charset="UTF-8"> <title></title> <style type="text/css"> * { margin:0; padding:0;} html,body,.parent{width:100%; height:100%;overflow:hidden;} .top{position:absolute;top:0;left:0;right:0;height:100px; background:#333;} .left{position:absolute;top:100px;left:0;bottom:50px;width:200px; background:red;} .right{position:absolute;overflow:auto;left:200px;right:0;top:100px;bottom:50px;background:blue;} .bottom{position:absolute;left:0;right:0;bottom:0;height:50px; background:#333;} </style> <script src="https://cdn.bootcss.com/jquery/1.8.3/jquery.js"></script> <script> $(function(){ $('#qh').on('click',function(){ var width = $(this).parent().width(); var j1 = (width == 50) ? {"width" : '200px'} : {"width" : '50px'} var j2 = (width == 50) ? {"left":"200px"} : {"left":"50px"} $(this).parent().stop().animate(j1,(width==50 ? 140 : 200)); $(this).parent().siblings('.right').stop().animate(j2,170); }); }); </script> </head> <body> <div class="parent"> <div class="top">top</div> <div class="left"> <button id="qh">切換</button> 11left<br/>left<br/>left<br/>left<br/>left<br/>left<br/>left<br/>left<br/>left<br/>left<br/>left<br/>left<br/>left<br/>leftleft<br/>left<br/>left<br/>left<br/><br/>left<br/>left<br/>left<br/>left<br/>left<br/>left<br/>left<br/>left<br/>left<br/>left<br/>left<br/>left<br/> </div> <div class="right"> 11right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/>right<br/> </div> <div class="bottom">bottom</div> </div> </body> </html>