不知道你需要的是不是這個方法
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Clear Search Box on Browser Close</title>
<script>
window.on-beforeunload = function(event) {
// 清除搜索框的值
document.getElementById('search-input').value = '';
};
</script>
</head>
<body>
<form action="/search" method="GET">
<input type="search" id="search-input" name="q">
<button type="submit">搜索</button>
</form>
</body>
</html>