<p><b>注释：</b>目前只有 Opera 支持 nav-* 属性。当您使用方向键导航时，请同时按下 Shift 键。</p>
<!DOCTYPE html>
<html>
<head>
<style>
button
{
position:absolute;
}
button#b1
top:20%;left:25%;
nav-index:1;
nav-right:#b2; nav-left:#b4;
nav-down:#b2; nav-up:#b4;
button#b2
top:40%;left:50%;
nav-index:2;
nav-right:#b3; nav-left:#b1;
nav-down:#b3; nav-up:#b1;