兼容性——原生button内边距在各个浏览器的兼容方法

<button id="btn"></button> 
<label for="btn">按钮</label> 
button { 
 position: absolute; 
 clip: rect(0 0 0 0); 
} 
label { 
 display: inline-block; 
 line-height: 20px; 
 padding: 10px; 
}