<!DOCTYPE html> <html> <head> <style> div.container { width:300px; border:10px solid blue; } div.box { box-sizing:border-box; -moz-box-sizing:border-box; /* Firefox */ -webkit-box-sizing:border-box; /* Safari */ width:50%; height:80px; padding:10px; border:10px solid red; float:left; } </style> </head> <body> <div class="container"> <div class="box">这个 div 占据左半部分。</div> <div class="box">这个 div 占据右半部分。</div> <div style="clear:both;"></div> </div> </body> </html>