1 <!DOCTYPE html> 2 <html> 3 <head> 4 <meta charset="utf-8"> 5 <title></title> 6 <style> 7 div{ 8 width: 300px; 9 height: 300px; 10 background-color: red; 11 filter:alpha(opacity=50); 12 opacity: 0.5; 13 } 14 </style> 15 <!-- 16 IE6、7下的透明度设置 17 filter:alpha(opacity=0 ~ 100); 18 --> 19 </head> 20 <body> 21 <div></div> 22 </body> 23 </html>