input type="radio"
нет события keyup https://developer.mozilla.org/ru/docs/Web/HTML/Ele...кстати SVG2 вышло ...слыхал ?
.dropdown:hover > .submenu,
.dropdown:hover > .subsubmenu
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Iframe SVG sprite</title>
</head>
<body>
<iframe src="sprite.svg" onload="this.before(this.contentDocument.children[0]);this.remove();"></iframe>
<svg><use href="#icon-favorite"></use></svg>
<svg><use href="#icon-face"></use></svg>
</body>
</html>
<svg xmlns="http://www.w3.org/2000/svg" width="0" height="0" aria-hidden="true">
<symbol id="icon-face" viewBox="0 0 24 24">
<path d="M9 11.75c-.69 0-1.25.56-1.25 1.25s.56 1.25 1.25 1.25 1.25-.56 1.25-1.25-.56-1.25-1.25-1.25zm6 0c-.69 0-1.25.56-1.25 1.25s.56 1.25 1.25 1.25 1.25-.56 1.25-1.25-.56-1.25-1.25-1.25zM12 2C6.48 2 2 6.48 2 12s4.48 10 10 10 10-4.48 10-10S17.52 2 12 2zm0 18c-4.41 0-8-3.59-8-8 0-.29.02-.58.05-.86 2.36-1.05 4.23-2.98 5.21-5.37C11.07 8.33 14.05 10 17.42 10c.78 0 1.53-.09 2.25-.26.21.71.33 1.47.33 2.26 0 4.41-3.59 8-8 8z"/><path fill="none" d="M0 0h24v24H0z"/>
</symbol>
<symbol id="icon-favorite" viewBox="0 0 24 24">
<path d="M0 0h24v24H0z" fill="none"/><path d="M12 21.35l-1.45-1.32C5.4 15.36 2 12.28 2 8.5 2 5.42 4.42 3 7.5 3c1.74 0 3.41.81 4.5 2.09C13.09 3.81 14.76 3 16.5 3 19.58 3 22 5.42 22 8.5c0 3.78-3.4 6.86-8.55 11.54L12 21.35z"/>
</symbol>
</svg>