css中按钮有四种状态
1. 普通状态
2. hover 鼠标悬停状态
3. active 点击状态
4. focus 取得焦点状态
.btn:focus{outline:0;} 可以去除按钮或a标签点击后的蓝色边框
下面的例子中.btn1用focus按钮会按下，不弹起
????????? .btn2用active按钮点击按下，会弹起
<button class="btn btn1">Save Settings</button><button class="btn btn2">Submit</button>
.btn{ ???appearance: none; ???background: #026aa7; ???color: #fff; ???font-size: 20px; ???padding: 0.65em 1em; ???border-radius: 4px; ???box-shadow: inset 0 -4px 0 0 rgba(0,0,0,0.2); ???margin-right: 1em; ???cursor: pointer; ???border:0;}.btn1:hover{ ???box-shadow: inset 0 -4px 0 0 rgba(0,0,0,0.6), 0 0 8px 0 rgba(0,0,0,0.5);}.btn1:focus{ ???position: relative; ???top: 4px; ???box-shadow: inset 0 3px 5px 0 rgba(0,0,0, 0.2); ???outline: 0;}.btn2:hover{ ???box-shadow: inset 0 -4px 0 0 rgba(0,0,0,0.6), 0 0 8px 0 rgba(0,0,0,0.5);}.btn2:active{ ???position: relative; ???top: 4px; ???box-shadow: inset 0 3px 5px 0 rgba(0,0,0,0.2); ???outline: 0;}.btn2:focus{ ???outline: 0;}css中按钮的四种状态
原文地址：http://www.cnblogs.com/mengff/p/8001511.html