1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>盒子的真实尺寸</title> 6 7 <style type="text/css"> 8 9 .box1,.box2,.box3{ 10 width: 50px; 11 height: 50px; 12 background-color: gold; 13 } 14 15 .box2,.box3{ 16 border:50px solid black; 17 } 18 19 .box3{ 20 padding:50px; 21 } 22 23 </style> 24 25 </head> 26 <body> 27 <div class="box1">1</div> 28 <br /> 29 <div class="box2">2</div> 30 <br /> 31 <div class="box3">3</div> 32 </body> 33 </html>