xxxxxxxxxx<html><meta charset="utf-8"><title>编程狮(w3cschool.cn)</title><head></head><style> .alpha1{ width:300px; height:200px; background-color:#FF0000; filter:Alpha(Opacity=30); } .ap2{ position:relative; } </style><body> <div class="alpha1"> <div class="ap2"> <p>背景为红色(#FF0000)，透明度20%。</p> </div> </div> </body></html>