```html
<!DOCTYPE html>
<html>
<head>
<title>当番決めアプリ</title>
</head>
<body>
<h1>当番決めアプリ</h1>
<input type="text" id="name1" placeholder="名前1">
<br>
<input type="text" id="name2" placeholder="名前2">
<br>
<input type="text" id="name3" placeholder="名前3">
<br>
<input type="text" id="name4" placeholder="名前4">
<br>
<input type="text" id="name5" placeholder="名前5">
<br>
<input type="text" id="name6" placeholder="名前6">
<br>
<button onclick="pickWinner()">抽選開始</button>
<p id="result"></p>
<script>
function pickWinner() {
const names = [
document.getElementById('name1').value,
document.getElementById('name2').value,
document.getElementById('name3').value,
document.getElementById('name4').value,
document.getElementById('name5').value,
document.getElementById('name6').value
];
const winnerIndex = Math.floor(Math.random() * names.length);
const winner = names[winnerIndex];
if (winner) {
document.getElementById('result').textContent = winner + " さんが当番です！";
} else {
document.getElementById('result').textContent = "誰かが当番です！";
}
}
</script>
</body>
</html>
```
